Immunohistochemistry (IHC), fluorescence in situ hybridization (FISH) and fluorescence reverse-transcription polymerase chain reaction (RT-PCR) were used to analyze the expression of HER2
protein, HER2 gene amplification and the
mRNA expression of ERCC1, TUBB3 and TYMS genes in 135 cases of gastric
carcinoma.
RESULTS: The expression rate of HER2
protein was 39.3% (53/135). Among these positive cases, patients with HER2
protein (3+) accounted for 9.6% (13/135), patients with HER2
protein (2+) accounted for 13.3% (18/135), and patients with HER2
protein (1+) accounted for 16.3% (22/135). The amplification rate of the HER2 gene was 35.8% (19/53). In the detection of the
mRNA expression of ERCC1, TUBB3 and TYMS, 45 patients had low and moderate single gene expression, 50 patients had low and moderate double gene expression, 22 patients had low and moderate
mRNA expression for ERCC1, TUBB3 and TYMS, and 18 patients had no low and moderate expression. Among the 53 patients with HER2
protein expression and 22 patients with low and moderate
mRNA expression of ERCC1, TUBB3 and TYMS, 12 patients received
chemotherapy and
trastuzumab. Follow-up results revealed that HER2 gene status was positively correlated with the
therapeutic effect of the combined treatment in patients with low
mRNA expression of ERCC1, TUBB3 and TYMS. Among these patients, five patients with extensive HER2 (3+), HER2 cluster-specific amplification, and low
mRNA expression of ERCC1, TUBB3 and TYMS had a total survival of up to 19.1 months.
CONCLUSIONS: The detection of HER2 in
gastric cancer is highly heterogeneity, and the combined detection of HER2
protein expression, HER2 gene amplification and chemosensitivity can provide important reference markers for the benefit of
antitumor drugs.