PURPOSE: The aim of this study is to examine the expression and correlations among EGFR, HER2, KRAS and RNA Binding Motif 5 (RBM5), a putative tumor suppressor that can modulate apoptosis by regulating alternative splicing of apoptosis-associated factors, moreover, to obtain a better understanding of the potential role played by RBM5 in the regulation of RBM5 tumor-suppressor activity in the lung cancer.
METHODS: Paired non-tumor and tumor samples were obtained from 60 lung cancer patients including 30 squamous carcinoma and 30 adenocarcinomas. mRNA and protein expression were examined by semi-quantitative reverse transcription-polymerase chain reaction and western blot. Data were analyzed using various statistical methods to test for correlations amongst the RBM5, EGFR, HER2 and KRAS.
RESULTS: RBM5 and HER2E,GFR ,KRAS mRNA and protein expression levels were reduced in tumor tissue compared the non-tumor tissue (P<0.05). Increased RBM5 and KRAS mRNA was found in 12/60(20%) tumor tissue. Increased HER2 mRNA was observed in 3/30(33%) of squamous carcinoma patients with increased RBM5 mRNA. Increased EGFR mRNA was found in 6/30 (20%) adenocarcinomas samples. RBM5 and HER2 mRNA and protein expression levels were significantly positively correlated (P<0.001) in both non-tumor and tumor tissue. whereas RBM5 and KRAS protein expression were only marginally correlated, in non-tumor tissue (P<0.05).
CONCLUSIONS: Decreased expressions of RBM5, KRAS and HER2 in tumor tissues suggest the genes might be involved in the carcinogenesis. The positive relations between RBM5 and HER2, RBM5 and KRAS further indicate the interaction amongst the genes may play a role in the pathology-specific lung cancer development
CLINICAL IMPLICATIONS: This study is the first investigation to examine expression and relation of RBM5, EGFR, HER2 and KRAS relation. Thus, although this was largely an exploratory study, signifiant results suggest that regulation of expression of this novel family of mRNA binding proteins is important to lung cancer progression.
DISCLOSURE: The following authors have nothing to disclose: Ke Wang, Hong Liang, Jie Zhang, Leslie Sutherland
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