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2014, Volume 30, Number 2, Page(s) 087-093     
[ Abstract (Turkish) ] [ Full Text ] [ PDF ] [ Similar Articles ]
DOI: 10.5146/tjpath.2014.01240
In Situ Hybridization Analysis of Invasive Breast Carcinomas with Immunohistochemically Negative Her-2 Status (A National Multicenter Study)
Sıtkı TUZLALI1, Ekrem YAVUZ1, Tülay CANDA2, Merih GÜRAY2, Melin Özgün GEÇER3, Yurdanur SÜLLÜ4, Cem SEZER5, Dinç SÜREN5, Serpil DİZBAY SAK6, Zerrin CALAY7, Şennur İLVAN7, Suzan ZORLUDEMİR8, Melek ERGİN8, Fatma Şeyda KARAVELİ9, Elif PEŞTERELİ9, Fatih ÖZDENER10, Kasım ÜSTÜNDAĞ10
1Departments of Pathology, 1İstanbul University, İstanbul Faculty of Medicine, İSTANBUL, TURKEY
2Dokuz Eylül University, Faculty of Medicine, İZMİR, TURKEY
3Lütfi Kırdar Kartal Training and Research Hospital, İSTANBUL,TURKEY
4Ondokuz Mayıs University, Faculty of Medicine, SAMSUN, TURKEY
5Antalya Training and Research Hospital, ANTALYA, TURKEY
6Ankara University, Faculty of Medicine, ANKARA, TURKEY
7İstanbul University, Cerrahpaşa Faculty of Medicine, İSTANBUL, TURKEY
8Çukurova University, Faculty of Medicine, ADANA, TURKEY
9Akdeniz University, Faculty of Medicine, ANTALYA, TURKEY
10Roche Müstahzarlari San. A.S., TURKEY
Keywords: In situ hybridization, Immunohistochemistry, Breast neoplasms, Her-2, Quality assurance

Objective: The aim of this study was to determine the rate of Her-2 gene amplification in breast cancer cases with a previous negative Her-2 result as determined by immunohistochemistry (score 0 or 1).

Material and Method: 552 cases of invasive breast carcinoma were assessed with the contribution of 9 centers. Previous immunohistochemistry score was either 0 or 1+ in all cases. These cases were re-tested by Her-2 silver in situ hybridization in the central laboratory. Her-2 gene amplification was defined as Her-2/CEP 17 ratio of more than 2.2. Cases with a ratio between 1.8 and 2.0 were defined as equivocal and cases with a ratio of less than 1.8 were defined as negative.

Results: Re-testing of the 552 cases with silver in situ hybridization showed a total of 22 cases with Her-2 gene amplification, of which 11 (3.2%) were found to be score 0, and 11 were found to be score 1+ (5.3%) by immunohistochemistry previously. Her-2 gene amplification rate of cases (score 0 and 1+) ranged from 0% to 10.48% among the centers. Polysomy was found in 28 (8.1%) of the score 0 cases and 25 (12.1%) among the score 1+ cases. Five (9.4%) of the cases with polysomy were found to be amplified, and 48 (90.6%) were not.

Conclusion: The results of the study show that a group of cases (3.98%) with a potential to benefit from anti-Her-2 therapy may be missed with the immunohistochemical method. This indicates the importance of quality assurance, especially in central laboratories with many breast cancer cases in daily practice.

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