Prognostic Significance of HER-2 Expression in Gastric Cancer

Abstract

In gastric cancers we purposed to examine the relationship between age, gender, invasion depth, lymph node metastasis,lymphovascular invasion, Lauren's classification, presence of perineural invasion and the expression of Human Epidermal GrowthReceptor (HER-2) by immunohistochemical (IHC) and dual-color silver-enhanced in situ hybridization (D-SISH) method. In our study,242 gastric resection materials that were studied HER-2 by IHC and/or D-SISH method referred to our department between January2014 and December 2017 for malignancy were included. The relationship between HER-2 expression rate and prognostic parameterswas investigated. No statistical relation was found between age and gender and HER-2 positivity in either method. No statisticallysignificant results were obtained between lymphovascular invasion, lymph node metastasis, presence of perineural invasion, depth ofinvasion and Lauren classification, and HER-2 positivity by immunohistochemical and D-SISH method. In our study, no statisticallysignificant results were obtained between important prognostic parameters and HER-2 positivity with either IHC or D-SISH method. In24.1% of the cases that were HER-2 positive by IHC, positivity was not observed with the D-SISH method. Also, 20.8% of the casesreported as immunohistochemically uncertain (equivocal) were seen as positive by the D-SISH method. Based on all these results, wewould like to state that HER-2 positivity / negativity determined by IHC can be changed by the D-SISH method. In addition, although itwas shown in our study that HER-2 has no prognostic significance in gastric carcinomas, it is reported in studies in the literature thatthe addition of Trastuzumab to chemotherapy increases survival. For this reason, we think that it would be more beneficial to applythe IHC and D SISH method together to obtain the true HER-2 result.