Expression of p42.3 in non-small cell lung cancer.

Background: Lung cancer is the most malignant tumor with the highest morbidity and mortality. This study aimed to investigate the role of the expression and the significance of the p42.3 gene in non-small cell lung cancer (NSCLC). Methods: Lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC) were analyzed based on the biological information data of The Cancer Genome Atlas (TCGA). Furthermore, 142 postoperative tumor tissue and normal tissue samples (70 cases of LUAD and 72 cases of LUSC) from NSCLC patients admitted to our hospital from 2005 to 2009 were retrospectively collected. Paraffin-embedded tissues were used to make the tissue microarrays (TMA), and the expression of the p42.3 protein was detected by immunohistochemical staining. Results: The expression of p42.3 in both LUAD and LUSC was significantly upregulated (P<0.01) compared with the normal lung tissues. The p42.3 expression was significantly higher than that of LUAD (P<0.01) in the LUSC group. LUSC had a lower level of p42.3 DNA methylation and a higher level of p42.3 DNA amplification than LUAD. The expression rate of p42.3 protein decreased in patients 70 years or older (P=0.029). High expression of the p42.3 protein was an independent factor for worse pathological differentiation (P=0.043). Conclusions: Both genetic and epigenetic alterations contributed to dysregulated p42.3 in NSCLC. Despite the temporary absence of TCGA-LUSC (TCGA data on LUSC) survival information, we observed that the up-regulated expression of p42.3 in LUSC was significantly higher than that in LUAD by analyzing the public database and reviewing the real-world data. Furthermore, a high expression of p42.3 protein was significantly correlated with poor differentiation of tumor tissues. Therefore, the prognostic value of p42.3 in LUSC deserves further study.