SEC62 and SEC63 Expression in Hepatocellular Carcinoma and Tumor-Surrounding Liver Tissue

Abstract

<b><i>Introduction:</i></b> The endoplasmic reticulum transmembrane proteins Sec61, Sec62, and Sec63 are responsible for the intracellular trafficking of precursor proteins and affect intracellular signaling. <i>SEC62</i> overexpression has been linked to various human cancers. Our aim was to investigate <i>SEC62</i> and <i>SEC63</i> expression in hepatocellular carcinoma (HCC) and surrounding liver tissue. <b><i>Patients and Methods:</i></b> Primary liver tissue was collected from 11 consecutive patients (70 ± 9 years; 10 men) who underwent HCC resection. In the HCC and the tumor-surrounding liver tissue we investigated <i>SEC62</i> und <i>SEC63</i> mRNA expression using quantitative real-time PCR. For Sec62, immunohistochemistry was performed. <b><i>Results:</i></b> <i>SEC62</i>and<i> SEC63</i> total mRNA contents were significantly (<i>p</i> = 0.001) higher in HCCs (C_T 22.5 ± 0.4 and 22.6 ± 0.3) when compared to the surrounding tissue (C_T 24.6 ± 0.6 and 25.1 ± 0.9). Using the comparative C_Tmethod, <i>SEC62</i> and <i>SEC63</i> expression in HCC was increased 5- and 8.1-fold, respectively, in comparison to surrounding tissue. For Sec62 immunohistochemistry, the mean immunoreactive scores (IRS) were 7.9 ± 2.9 for HCC and 4.8 ± 1.2 for non-tumorous liver (<i>p</i> = 0.027). The mean IRS in HCC were 5.7 ± 3.5 and 8.9 ± 2.3 for patients without (<i>n</i> = 3) and with tumor recurrence (<i>n</i> = 8), respectively. <b><i>Conclusions:</i></b> Overexpression of <i>SEC62</i> and <i>SEC63</i> is a common feature of HCC. The role of Sec62 as a prognostic marker for tumor recurrence after surgery and its potential role in treatment stratification must be addressed in future studies.