Upregulated Seizure-Related 6 Homolog-Like 2 Is a Prognostic Predictor of Hepatocellular Carcinoma

Abstract

Seizure-related 6 homolog-like 2 ( SEZ6L2 ), which is localized on the cell surface, has been found to be associated with tumor angiogenesis and lung cancer progression. However, the role of SEZ6L2 in hepatocellular carcinoma (HCC) is still unclear. We obtained data from The Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus (GEO) to investigate SEZ6L2 expression and regulation in HCC. Then, HCC tissue samples were collected to verify SEZ6L2 by quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemical staining (IHC). Patient information was collected for survival and prognosis analysis. qRT-PCR, IHC, and bioinformatics analysis showed that the SEZ6L2 protein was highly expressed in HCC samples. Clinical data showed that high SEZ6L2 protein expression was correlated with tumor-node-metastasis (TNM) stages (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mi>P</mml:mi><mml:mo>=</mml:mo><mml:mn>0.046</mml:mn></mml:math>), tumor number (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M2"><mml:mi>P</mml:mi><mml:mo>=</mml:mo><mml:mn>0.016</mml:mn></mml:math>), and tumor size (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M3"><mml:mi>P</mml:mi><mml:mo>=</mml:mo><mml:mn>0.029</mml:mn></mml:math>). Meanwhile, SEZ6L2 overexpression was closely associated with poor overall survival and disease-free survival in HCC patients. Moreover, SEZ6L2 is an independent prognostic predictor for the survival of HCC patients. This study suggests a significant correlation between SEZ6L2 and HCC, which means that SEZ6L2 may potentially serve as a useful prognostic biomarker for HCC patients.