Differential clinical significance of COL5A1 and COL5A2 in tongue squamous cell carcinoma

Background Type V collagen (COL5), in the functional heterotrimer [alpha 1(V)(2)alpha 2(V)] isoform, participates in the malignancies of various cancers. However, its role in tongue squamous cell carcinoma (TSCC) remains unclear. Materials and Methods The expression levels of COL5A1 and COL5A2 polypeptide chains were examined using the tissue microarray from 245 TSCC patients with immunohistochemistry. Paired t test and Wilcoxon signed-rank test were performed for comparisons among the groups. Survival rates were estimated by using the Kaplan-Meier method and compared with log-rank tests. A Cox proportional hazards model was used to evaluate the impact of protein expression level on survival rate. Results Expression level of COL5A1 was significantly increased in tumor tissues (P < 0.001) compared to that in corresponding adjacent normal tissues. High expression level of COL5A1 was associated with advanced pathological stage (III, IV, P = 0.015) and lymph node metastasis (P = 0.005) of TSCC patients. High expression level of COL5A1 was also correlated with poor disease-specific survival (DSS, P = 0.001) and disease-free survival (DFS, P = 0.003) in TSCC patients. However, high expression level of COL5A2 was correlated with better DFS in TSCC patients (P = 0.043). Moreover, co-expression level of high (COL5A1)(2)/low (COL5A2) heterotrimer was correlated with worse DSS (P = 0.004) and DFS (P = 0.004). Conclusion COL5A1 is an unfavorable factor for tumorigenesis, clinicopathological outcomes, and prognosis, whereas COL5A2 is only a favorable factor for prognosis in TSCC. The co-expression of high (COL5A1)2/low (COL5A2) heterotrimer is a more potential unfavorable factor for prognosis in TSCC.