Comparative Assessment of Immunohistochemistry (IHC), Fluorescence In Situ Hybridization (FISH), and Silver-Enhanced In Situ Hybridization (SISH) for Evaluation of HER2 Gene Status in Breast Carcinoma
Y Ryu, H Jeong, Y Kim, B Kim, H Kim, A Kim. Korea University Guro Hospital, Seoul, Korea
Background: HER2 gene amplification occurs in 15% to 25% of breast cancers and has implications for treatment and prognosis. The established and approved method for HER2 gene status is IHC in combination with FISH techniques. Recently, new direct evaluation technique, silver enhanced in situ hybridization (SISH) was developed. This study was performed to evaluate SISH technique for clinical use.
Design: We studied 729 cases of excised breast carcinoma specimen by IHC (anti-HER2 Mouse Monoclonal Antibody, NeoMarkers, Fremont, CA USA), FISH (PathVysion® HER-2 DNA Probe Kit, Abbott/Vysis Abbott Park. ILL USA), and SISH (INFORM® HER2 SISH DNA probe, Ventana, Tucson, AZ USA) using tissue microarray (TMA; AccuMaxTM array, ISU Abxis, Seoul, Korea) and evaluated accordance of two techniques. Interpretation SISH, IHC and FISH was performed according to Interpretation Guide INFROMTMHER2 (Roche) and ASCO/CAP guideline, respectively.
Results: Her2 gene status could be assessed by IHC, FISH and SISH in 504 cases. The IHC results show 498 (score 0), 13 (score1), 29 (score2), and 99 cases (score3). The results of FISH show 369 (negative), 0 (equivocal), and 135 cases (positive). The results of SISH show 363 (negative), 6 (equivocal), and 135 cases (positive). 7 cases among 369 cases with Her2 negativity in FISH showed Her2 gene amplification in SISH. The accordance rate of SISH and FISH is 98.4% (kappa value 0.96).
Conclusions: SISH technique is effective modality comparable with FISH to evaluate HER2 gene amplification in breast carcinoma.
Tuesday, March 23, 2010 1:00 PM
Poster Session IV # 9, Tuesday Afternoon