Microsatellite Instability Status and the Expression of p16 and Cyclin D1 Proteins in Uterine Adenosarcoma and Their Clinicopathological Significance
Alev OK ATILGAN1, Eda YILMAZ AKCAY1, Ozlem OZEN1, A. Nihan HABERAL REYHAN1, Ali AYHAN2
1Department of Pathology, Baskent University, Faculty of Medicine, ANKARA, TURKEY
2Department of Obstetrics and Gynecology, Division of Gynecologic Oncology, Baskent University, Faculty of Medicine, ANKARA, TURKEY
Keywords: Adenosarcoma, Microsatellite instability, p16, Cyclin D1
Uterine adenosarcoma has low malignant potential, except in cases with sarcomatous overgrowth (SOG) and a high-grade morphology.
We here point out the prognostic clinicopathological and immunohistochemical features as well as the microsatellite instability (MSI) status of
high- and low-grade adenosarcomas.
Material and Method: In this study, DNA mismatch repair proteins, p16, cyclin D1, ER, PR, and CD10 were examined in uterine adenosarcoma
cases using immunohistochemistry. The association between these proteins and clinicopathological parameters was also evaluated.
Results: ER, PR and CD10 expressions were lower and weaker in high-grade adenosarcomas with SOG compared to low-grade adenosarcomas
without SOG (p < 0.05). p16 positivity was more frequent in high-grade adenosarcomas than low-grade adenosarcomas (p < 0.05). There was
no statistically significant difference between cyclin D1 positivity, MSI, and other clinicopathological parameters (p ≥ 0.05). Cyclin D1 positivity
and loss of CD10 expression were associated with shorter disease-free survival (DFS). Loss of ER and CD10 expression was associated with
shorter overall survival (OS) (p < 0.05). MSI was not associated with DFS or OS (p ≥ 0.05).
Conclusion: These results suggested that p16 positivity, and loss of ER, PR, and CD10 expression were predictors of high-grade morphology.
Additionally, the current study showed that cyclin D1-positive tumors had high recurrence rates; however, no significant relationships were
found between MSI and DFS or OS in patients with uterine adenosarcoma. Further investigations are required to determine the importance of
p16, cyclin D1, and MSI in uterine adenosarcomas.
Uterine adenosarcoma, a rare mixed epithelial and mesenchymal
tumor of the female genital tract, accounts for 5%
and 10% of all uterine sarcomas 1
. These tumors typically
comprise benign epithelial elements and low-grade malignant
mesenchymal components. The tumor exhibits a biphasic
appearance consisting of tubular, dilated cleft-like
glands lined by a benign-appearing epithelium and malignant
cellular stroma 2,3
. Stroma is typically a low-grade
sarcoma that usually has no specific line of differentiation,
although some consider it to resemble endometrial stromal
. The presence of sarcoma without any epithelial
component in > 25% of the tumor refers to sarcomatous
overgrowth (SOG). It is generally associated with
deeper myometrial involvement, lymphovascular invasion,
and worse prognosis and recurrence 2-4
In the literature, it has been shown that SOG tends to be
associated with a high-grade morphology. However, it should be kept in mind that there may be minor highgrade
morphology in the tumor without SOG. In addition,
SOG can also be seen in purely low-grade adenosarcomas
5. Almost all studies about adenosarcomas have focused
on the presence of SOG in the literature. A few studies
have distinguished between low-grade adenosarcoma and
high-grade adenosarcoma 5-7. Soslow and Longacre
have proposed that high-grade adenosarcomas have an
aggressive course 8. It has been thought that high-grade
morphology may be an independent factor separate from
SOG 5. Hodgson et al. also showed that high-grade
adenosarcomas have distinctive molecular characteristics
along with morphologic and clinic features from lowgrade
adenosarcomas 5. Although the latest WHO
2020 classification of female genital tract tumors does not
yet include the grading of uterine adenosarcomas, the
College of American Pathologists (CAP, 2018) protocol
recommends recording in the pathology report whether
the stromal component is morphologically “low-grade” or “high-grade” for adenosarcomas without sarcomatous
overgrowth. A high-grade morphology is defined as
sarcoma with severe nuclear atypia and pleomorphism
identifiable at low power magnification, characterized by
enlarged ovoid or spindle nuclei with coarse chromatin and
prominent nucleoli 5. However, there is not yet a cut-off
value on nuclear size and mitotic count in the distinction
between high- and low-grade morphology.
The deoxyribonucleic acid (DNA) mismatch repair
(MMR) system protects the human genome from intrinsic
and extrinsic factors via short repeating motifs in the DNA
called microsatellites, which repair mismatching errors such
as inappropriate nucleotide insertions and deletions as well
as single nucleotides. When these errors are not corrected,
genomic stability is disrupted during DNA replication
and recombination 9. Deficient MMR (dMMR) is a
major cause of genomic instability and results in the
accumulation of numerous mutations in microsatellite
sequences, resulting in microsatellite instability (MSI) 9,10. The primary DNA MMR proteins associated with
MSI by inactivation are MutL protein homolog 1 (MLH1),
MutS protein homolog 2 (MSH2), MutS protein homolog 6
(MSH6), and postmeiotic segregation increased 2 (PMS2).
These proteins interact as heterodimers, i.e., MSH2 couples
with MSH6, and MLH1 couples with PMS2. MSI has been
most closely studied in colorectal cancers; however, it has
been found in various cancer types, including gynecological
tumors 9,11. In the context of uterine adenosarcomas,
MSI and dMMR are not yet fully understood, and their
clinical significance as prognostic factors has not yet been
The p16 protein plays a role as a tumor suppressor that
negatively regulates the cell cycle by inhibiting the activity
of cyclin D-dependent kinases to prevent phosphorylation
of the RB family protein and cyclin D1 bind to cdk4,
leading to the inactivation of RB genes 12,13. Gene
mutation, deletion, or epigenetic silencing, or in cases
where overexpression of cyclin D1 occurs, can lead to RB
or p16 inactivation and abnormal cell proliferation 13.
Various cancers involving the mutation or overexpression
of p16 and cyclin D1 have been identified 13-15.
The aim of this study was twofold. First, p16, cyclin D1,
ER, PR, and CD10 expression in uterine adenosarcomas
was evaluated to determine the possible impacts on
the prognosis. Second, we investigated the frequency
and the prognostic effect of MSI by evaluating the
immunohistochemical expression of MMR proteins in
Twenty cases of uterine adenosarcoma, diagnosed between
January 1, 2009 and December 30, 2020, were included
in this study. The research was approved by the Ethics
Committee of the Faculty of Medicine (KA21/419), and all
protocols conformed to the ethical guidelines of the 1975
Helsinki Declaration. The hospital records of the included
patients were reviewed, and the clinical follow-up findings
were noted. The diagnosis of adenosarcoma and SOG were
based on the standard criteria adopted by the World Health
Organization (2020). Each tumor was classified as either
low or high grade. A high-grade morphology was defined
as sarcoma with severe nuclear atypia and pleomorphism
identifiable at low power magnification, characterized by
enlarged ovoid or spindle nuclei with coarse chromatin
and prominent nucleoli 5
. The tumor stage of all patients
was noted according to the International Federation of
Gynecology and Obstetrics (FIGO Cancer Report 2018)
Tissue Microarray and Immunohistochemistry
Two representative foci involving different areas (2 mm
in diameter) supporting the diagnosis and showing both
epithelial and stromal areas including high-grade or lowgrade
morphology were punched from the original and
inserted into a new paraffin block. Serial-sectioned slides
were obtained with a conventional microtome of 4-μmthickness
for immunohistochemistry using the following
primary antibodies: estrogen receptor (ER), progesterone
receptor (PR), CD10, cyclin D1, p16, CD117, MLH-1,
PMS-2, MSH-2, and MSH-6. We used a Dako Omnis
(Agilent, Santa Clara, CA) system and EnVision FLEX
staining kits to perform immunohistochemical staining.
Sections were maintained at 60°C for 60 min and dewaxed
using a Clearify (Dako) solution at 25°C for 1 min in an
autostainer. Heat-induced antigen retrieval was performed
using an ethylenediaminetetraacetic acid/citrate buffer
(EnVision FLEX HRS, high pH) at 97°C for 60 min for
antibodies (EnVision FLEX HRS). The sections were
rinsed with a wash buffer, and sections were incubated
with anti-MLH1 (clone ES05, mouse), PMS2 (clone EP51,
rabbit), MSH2 (clone FE11, mouse), and MSH6 (clone
EP49, rabbit), ER (clone EP1, rabbit), PR (clone PgR636,
mouse), CD10 (clone 56C6, mouse), cyclin D1 (clone
EP12, rabbit) (all Ready-to-Use, all from DAKO), and p16
(clone Y123261, Mouse, ready-to-use from ABM). Sections
were then incubated with a peroxidase solution (EnVision
FLEX peroxidase-blocking reagent; Dako) for 3 min. These were rinsed, reactivated in an EnVision FLEX/horseradish
peroxidase solution for 20 min, incubated for 5 min with
an EnVision FLEX substrate working solution (DAKO) for
visualization, and then counterstained with hematoxylin.
Appropriate positive and negative controls were used.
Analysis of Immunohistochemical Staining
Two researchers (AOA, EYA) independently scored the
immunohistochemistry-stained slides using a doubleheaded
microscope without prior knowledge of any
relevant clinicopathological information. Staining was
analyzed only when each core included ≥ 50% tumor
tissue. For ER, PR, and CD10, the intensity was scored as
negative (0), weak (1+), moderate (2+), or strong (3+) and
the percentage of positive tumor cells was scored from 0 to
100%. The intensity score was multiplied by the percentage
and the H-score was used as the final semi-quantitative
score for each case 6. The immunostaining was considered
mild when H-score was ≤ 100, moderate when 101-200, and
strong when 201-300 (Figure 1). Tumors showing ≥ 70%
moderate to strong nuclear staining for cyclin D1 and p16
were considered as positive (16) (Figure 2). We assessed
loss of immunohistochemical expression of MMR proteins
in tumor cells in the presence of positive internal control.
Tumors with intact immunohistochemical expression of all
four MMR proteins were considered microsatellite stable
(MSS), whereas tumors with loss of immunohistochemical expression of one or more MMR proteins were considered
to show MSI (Figure 3). Membrane staining was interpreted
as indicating CD117 positivity.
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|Figure 1: Immunohistochemical staining of ER, PR, CD10. A) ER, B) PR, C) CD10 strong positivity. D) ER, E) PR, F) CD10 negativity
(x100 original magnification).
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|Figure 2: Immunohistochemical
staining of p16, cyclin D1. A) p16,
B) cyclin D1 strong positivity.
D) p16, E) cyclin D1 negativity
(x100 original magnification).
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|Figure 3: Immunohistochemical staining of MMR proteins A) retained MLH1 protein,
B) loss of MLH1 protein, C) retained PMS2 protein, D) loss of PMS2 protein,
E) retained MSH2 protein, F) loss of MSH2 protein, G) retained MSH6 protein
(x100 original magnification).
Statistical analyses were performed using the Statistical
Package for the Social Sciences version 26.0 (SPSS Inc., Chicago,
IL, USA). The variables were investigated using analytical
methods (Shapiro-Wilk test) to determine whether
or not they were normally distributed. Descriptive analyses
were presented using median (minimum (min)-Maximum
(max)) for numerical variables. Since the variables did not
show a normal distribution, non-parametric tests were
performed. Comparison of numerical data was performed
using the nonparametric Mann–Whitney test and Kruskal-
Wallis test. Qualitative variables were examined using the
Fisher’s exact test. Disease-free survival (DFS) and overall
survival (OS) rates were estimated using the Kaplan-Meier
method and were compared using the long-rank test. A pvalue
of < 0.05 was considered statistically significant.
The median (min-max) age at the time of diagnosis was 55
(15-78) years. Among the 20 tumors, 17 (85%) arose from
the endometrium (3 from the lower uterine segment), 1
(5%) from the adenomyotic foci of the myometrium, and 2 (10%) from the cervix. The tumors ranged from 2 to 15
cm in diameter (median 7.3 cm). At the time of diagnosis, 4
(20%) of the tumors were FIGO stage Ia, 12 (60%) stage Ib,
3 (15%) stage Ic, and 1 (5%) stage IV disease. FIGO stage Ia
and Ib were accepted as early stages, while stages Ic and IV
were considered advanced stages.
Sixteen tumors showed myometrial or cervical invasion.
Two tumors arose from the endometrium, and one tumor
had no myometrial or cervical stromal invasion arising from
the cervix uteri. One tumor was limited to the adenomyotic
focus arising from the myometrium.
Among the 20 tumors, 11 (55%) had a high-grade component
(all of which had SOG), and 9 (45%) tumors were
purely low grade (none had SOG) (p≤0.001). Seven tumors
had heterologous elements, including chondrosarcomatous
differentiation in 1 case, rhabdomyosarcomatous differentiation
in 5, and benign cartilage differentiation in 1. All
of the tumors containing malignant heterologous elements
were high grade (p=0.045). The median (min-max) mitotic
count was 8 (3-13) per 10 high powered fields (HPFs) in the
high-grade adenosarcoma group vs. 3 (2-6)/10 HPFs in the
low-grade adenosarcoma group (p=0.002). Of the 20 tumors,
4 (20%, all high grade) had lymphovascular invasion
(p=0.045). One (5%) of the tumors that had lymph node
metastases showed thoracal vertebra and lung metastases
at the time of diagnosis. None of the tumors had omental
metastases and positive peritoneal cytology.
There was no statistically significant difference between
the high- and low-grade adenosarcoma groups in terms of
age at diagnosis, tumor size, presence/depth of myometrial
invasion, or FIGO stage (p≥0.05).
The Association of ER, PR, CD10 Expressions with
ER, PR and CD10 expressions were lower and weaker in
high-grade adenosarcomas with SOG compared to lowgrade
adenosarcomas without SOG (p=0.022, p=0.017,
p≤0.001, respectively). ER and PR expressions were lower and
weaker in adenosarcomas containing heterologous elements
than in those without heterologous elements (p=0.005,
p=0.044, respectively). There was no statistically significant
association between ER, PR and CD10 expressions and other
clinicopathological parameters (p≥0.05) (Table I).
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|Table I: The association between ER/PR/CD10 expression and clinicopathologic features.
The Association of p16, cyclin D1, and CD117
Expression with Clinicopathological Characteristics
All high-grade adenosarcomas had p16 positivity, and
5 (55.6%) of 9 low-grade adenosarcomas exhibited p16
positivity (p=0.026). p16 positivity was more frequent in adenosarcomas containing SOG than in those without SOG.
(p=0.026). There was no statistically significant association
between p16 positivity and other clinicopathological
parameters (p≥0.05) (Table II).
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|Table II: The association between p16/cyclin D1 expression, Microsatellite Instability Status and clinicopathologic features.
Five (45.5%) of the 11 high-grade adenosarcomas and
3 (33.3%) of the 9 low-grade adenosarcomas showed
cyclin D1 positivity. However, there was no significant
association between cyclin D1 positivity and tumor grade
(p=0.670). There was no statistically significant association
between cyclin D1 positivity and other clinicopathological
parameters (p≥0.05) (Table II).
Neither high grade nor low-grade adenosarcoma exhibited
The Association of MMR Protein Expression with
The loss of MLH1, PMS2, MSH2, and MSH6 expression
was detected in 4 (20%), 1 (5%), 1 (5%) and 0 (0%) cases,
respectively. Out of 20 adenosarcomas, 4 (20%) presented
a loss of expression for at least one MMR protein; 1 (5%)
showed a loss of three proteins (MLH1, PMS2, MSH2), 3
(15%) showed a loss of one MMR protein (MLH1). The
remaining 16 tumors (80%) were positive for four MMR
proteins. As a result, 16 tumors that expressed all MMR
proteins were accepted as MSS, and four tumors that
showed clonal loss of at least one of the MMR proteins
were accepted as MSI. Accordingly, the frequency of MSI
in adenosarcoma was 20% in our study group (Figure 3).
None of the patients underwent the MLH1 methylation
test and genetic consultation. None of the patients had a
known history of Lynch syndrome.
Two (18.2%) of 11 high-grade adenosarcomas and two
(22.2%) of 9 low-grade adenosarcomas were MSI. There
was no statistically significant association between MSI
and tumor grade and other clinicopathologic parameters
(p≥0.05) (Table II).
The median (min-max) time for recurrence was 9.6 (5.7-
19.4) months. Only four (20%) patients showed recurrence
occurring in the upper abdominal region and vaginal cuff.
All of the tumors (100%) that showed recurrence were
high-grade, and 9 of 16 (56.3%) nonrecurring tumors were
low-grade. Univariate Kaplan–Meier/ Log-rank analyses
revealed that high-grade adenosarcomas and tumors
with SOG tended to show a higher incidence of disease
recurrence (p=0.03). While the median (min-max) DFS
time of patients with advanced FIGO stage was 7.2 (3.9-140.8) months, for patients with early FIGO stage this was
57.0 (2.5-102.0) months. Adenosarcomas with advanced
FIGO stage had significantly decreased DFS than those
with early FIGO stage (p=0.001). Adenosarcomas with
higher mitoses had significantly decreased DFS than those
with lower mitoses (p≤0.001). Adenosarcomas with deeper
myometrial invasion also had significantly decreased DFS
than those with superficial or any myometrial invasion
(p=0.029). However, the presence of lymphovascular
invasion, heterologous elements did not affect the DFS rate
ER, PR, and CD10 expression of the tumors showed that
recurrence was lower and weaker than in those without
recurrence. We found that CD10 expression, not ER and
PR expression, affected the DFS rate (p=0.014). Cyclin D1
positivity tended to show a higher incidence of disease
recurrence (p=0.014). All tumors that had recurrence showed p16 positivity. However, p16 positivity had no
impact on the DFS rate (p≥0.05). Four of 16 patients
with MSS adenosarcoma showed recurrence. None of
the patients with MSI adenosarcoma showed recurrence.
However, MSI status did not affect the DFS rate (p≥0.05)
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|Figure 4: The Kaplan-Meier curves of A) ER, B) PR, C) CD10, D) p16, E) cyclin D1, F) MSI status for disease-free survival. Patients with
loss of CD10 expression and cyclin D1 positivity had a significantly shorter disease-free survival.
The median (min-max) follow-up time was 60.6 (2.5-140)
months. Four (20%) patients died because of their disease.
Two (10%) patients died due to cardiovascular deficiency
without evidence of uterine adenosarcoma recurrence and
were considered censored. Two (10%) patients were alive
and still living with the disease, and 12 (60%) patients were
alive with no evidence of disease.
All the patients who died of disease were high-grade, and all
the patients with low-grade tumors were alive. The median (min-max) OS of patients with high-grade adenosarcoma
was 34.1 (2.5-102.0) months, and for patients with low-grade
adenosarcoma it was 90.5 (14.3-140.8) months. Univariate
Kaplan–Meier/ Log-rank analyses revealed that high-grade
adenosarcomas and tumors with SOG statistically showed
marginal significance (p=0.05). While the median (minmax)
OS time of patients with advanced FIGO stage was
43.1 (3.9-140.8) months, for patients with early FIGO
stage this was 60.7 (2.5-102.0) months. Advanced FIGO
stage, presence of lymphovascular invasion, and higher
mitotic count and heterologous elements were significantly
associated with decreased OS rates (p=0.025, p≤0.001, p
≤.001, p = 0.038, respectively). Myometrial invasion was
not significantly associated with the OS rate (p=0.189).
The loss of ER and CD10 immunoreactivity was associated
with a decreased OS rate (p=0.042, p=0.028, respectively).
While PR, p16, and cyclin D1 immunoreactivity were not significantly associated with the OS rate (p≥0.05). Three
of 16 patients with MSS adenosarcoma died, and one of 4
patients with MSI adenosarcoma died; however, the MSI
status did not affect the OS rate (p≥0.05) (Figure 5).
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|Figure 5: The Kaplan-Meier curves of A) ER, B) PR, C) CD10, D) p16, E) cyclin D1, F) MSI status for overall survival. Patients with loss
of ER/CD10 expression had a significantly shorter overall survival.
Uterine adenosarcoma comprises benign epithelial
elements and malignant mesenchymal components
that include a leaf-like architecture, periglandular
condensation, mild/moderate cytologic atypia, and
variable mitotic activity 2,3
. These tumors generally have
low malignant potential and a good prognosis following
surgery. However, SOG is typically associated with a poor
prognosis and recurrence 2-4
. Additionally, although
SOG is typically associated with a high-grade morphology,
it can also be observed in low-grade adenosarcoma.
Therefore, classifying adenosarcomas as high- or lowgrade
is useful for predicting tumor behavior. Soslow and Longacre first proposed that high-grade adenosarcomas
have an aggressive course 8
. Hodgson et al. reported that
high-grade adenosarcoma was frequently associated with
large tumor size and a high mitotic index 5
. In this study, we found a significant association between high-grade
adenosarcoma and the presence of SOG, lymphovascular
invasion, heterologous elements, and a high mitotic count
but no relation with FIGO stage or myometrial invasion. Additionally, we found that a high-grade morphology had
a significant impact on the DFS and OS rates.
The additional clinicopathological features of the tumors
in our series were concordant with those of the previously
reported studies. Similar to outcomes from the literature,
we found that patients with SOG had significantly shorter
DFS and OS rates than patients without SOG, while
lymphovascular invasion and stage also had a significant
impact on DFS and OS rates 6,17,18. Additionally, we
found that mitotic count had a significant impact on DFS
and OS rates in our study.
Several studies have described the immunohistochemical
features of adenosarcoma. The mesenchymal component
of adenosarcoma has a similar immunophenotype to lowgrade
endometrial stromal sarcoma. Both tumors express
ER, PR, CD10, and WT1 6,19. Additionally, low-grade
stromal components without sarcomatous overgrowth
have shown a higher percentage of ER and PR positivity
compared to high-grade sarcomatous components in
adenosarcoma 6,19,20. Furthermore, decreased CD10
expression in adenosarcoma with sarcomatous overgrowth
was observed compared with classic adenosarcoma 6,19,20. In this study, we found that adenosarcomas with a
high-grade morphology reflected lower ER, PR, and CD10
immunoreactivity than those with a low-grade morphology.
6,19,20. We also showed that ER and PR immunoreactivity
were lower and weaker in adenosarcomas that had
heterologous elements compared to adenosarcomas that
had any heterologous elements. Additionally, the loss of ER
and CD10 expression in the stromal component of uterine
adenosarcoma had a significant impact on OS. The loss of
CD10 expression, but not of ER and PR expression, had a
significant impact on DFS.
p16 and cyclin D1 play a specific role in the regulation of
the G1-to-S phase in cell cycles 12,13. The overexpression
of cyclin D1 has been observed in various types of human
malignancies, including uterine sarcomas 15. There
is limited data regarding cyclin D1 immunoreactivity
in uterine sarcomas. Cyclin D1 immunostaining was
specifically observed in endometrial stromal sarcoma
(ESS), particularly YWHAE-FAM22 rearranged ESS
16. However, cyclin D1 has also been expressed in
undifferentiated endometrial sarcoma and leiomyosarcoma
without the YWHAE-FAM22 rearrangement 16.
Gallardo et al. studied cyclin D1 immunoreactivity in
uterine adenosarcoma, carcinosarcoma, endometrial
stromal tumors, endometrial polyps, and endometriosis
6. The authors found no differences between cyclin D1
immunoreactivity and uterine adenosarcoma or other
lesions 6. Omi et al. have reported that 3 of 7 uterine adenosarcomas had cyclin D1 immunoreactivity (2 had
a high-grade morphology and SOG, and one was a lowgrade
type without SOG) 7. Lee et al. have reported that
25 adenosarcomas (8 of which had SOG) had no cyclin D1
immunoreactivity 16. Sharma and Prachi reported that
one adenosarcoma with SOG showed cyclin D1 positivity
21. In the present study, we found that five (45.5%)
of 11 high-grade adenosarcomas (all had SOG) and 3
(33.3%) of 9 low-grade adenosarcomas exhibited cyclin
D1 immunoreactivity; however, no significant association
was found between cyclin D1 immunoreactivity and tumor
grade, the presence of SOG, or other clinicopathological
parameters. In addition, our study indicated that cyclin D1
is positively correlated with an unfavorable DFS rate but
not with OS.
In current gynecological pathology practice, diffuse blocktype
p16 expression is a surrogate marker for human papillomavirus
(HPV) infection in cervical lesions. Additionally,
p16 positivity is linked to non-HPV-related mechanisms,
and p16 immunoreactivity has also been examined in a few
studies involving uterine adenosarcoma 6. Gallardo and
Prat demonstrated weak p16 immunoreactivity in endometrial
polyp and endometrial stromal sarcomas, moderate
p16 immunoreactivity in uterine adenosarcoma, and
strong p16 immunoreactivity in carcinosarcoma 6. In the
current study, the vast majority of cases (80%) exhibited
p16 immunoreactivity. Furthermore, all high-grade adenosarcomas
showed p16 immunoreactivity, and a significant
correlation was found between the two. As such, p16 immunoreactivity
was critical for confirming the presence of
a high-grade morphology. All recurrent tumors showed
p16 immunoreactivity. However, we demonstrated that
p16 immunoreactivity did not affect DFS or OS rates. The
current study observed CD117 negativity in uterine adenosarcoma
to be similar to that reported in studies on mesenchymal
tumors of the uterus 19,22. In contrast, other
studies have shown a variable frequency of CD117 immunoreactivity
in uterine sarcoma, but no mutation has been
indicated to date 23-25.
A mutation in one of the repair proteins will lead to
impairment in the DNA MMR system. Mismatch repair
deficiency giving rise to MSI and malignancy has been
identified in various cancer types, including gynecological
cancers 9-11. In existing studies, MSI was more frequently
found in uterine carcinosarcoma compared with other
uterine sarcomas including leiomyosarcoma, endometrial
stromal sarcoma, and rhabdomyosarcoma 26-28. The
MSI status of uterine adenosarcoma and its prognostic
effects have been less frequently studied. Risinger et al.
evaluated only one adenosarcoma case for MSI status, which was found to be microsatellite-stable 29. Hoang
et al. reported 11 adenosarcomas that showed intact MMR
protein expression 26. In contrast to these studies, we
demonstrated that 20% of cases had MSI. All MSI tumors
had MLH1 loss, and one tumor had PMS2 and MSH2 loss
in addition to MLH1 loss. Microsatellite instability is also
known to be prognostic within various cancer types. Some
studies provide evidence that increasing microsatellite
stability is positively correlated with survival time in various
cancer types 30. However, the current study showed MSI
had no impact on OS or DFS rates in uterine adenosarcoma
There were some limitations to our study. First, due to the
rarity of adenosarcoma and the single-center nature of this
study, the number of patients included in our research was
limited. Second, we evaluated ER, PR, CD10, p16, cyclin
D1, and MMR protein expressions using TMA cores, which
were prone to assessment limitations. Third, we detected
protein expression only by immunohistochemistry.
We could not perform polymerase chain reaction or a
methylation test of the MLH1. Consequently, these results
should be validated by additional multi-center studies
using a larger patient cohort.
In conclusion, the current study aimed to highlight the
prognostic clinicopathological and immunohistochemical
features of adenosarcoma. p16 positivity, along with
the loss of ER, PR, and CD10 expression, were predictors
of a high-grade morphology. We identified a high-grade
tumor, the presence of sarcomatous overgrowth, lymphovascular
invasion, a high mitotic count, and the presence
of heterologous elements as poor prognostic factors for
patients with uterine adenosarcoma. Additionally, the current
study showed that cyclin D1-positive tumors had high
recurrence rates; however, no significant relationships were
found between MSI and DFS or OS rates in patients with
uterine adenosarcoma. Accordingly, immunohistological
features, along with tumor grade, may be useful for predicting
the behavior of a tumor. Additional studies are needed
to enable accurate predictions of the effect of p16 and cyclin
D1 expression and MSI in uterine adenosarcoma cases.
Conflict of Interest
The authors declare no conflict of interest.
Concept: AOA, Design: AOA, OO, NHR, Data collection or
processing: AOA, EYA, Analysis or Interpretation: AOA, EYA, OO,
NHR, Literature search: AOA, Writing: AOA, OO, NHR, Approval:
AOA, EYA, OO, NHY, AA.
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