CBX3/HP1γ is upregulated in tongue squamous cell carcinoma and is associated with an unfavorable prognosis

Increased expression of CBX3/HP1γ, a core component of heterochromatin protein 1, has recently proved to be involved in human tumorigenesis and patient prognosis. The present study aimed to investigate the expression of CBX3/HP1γ and its clinicopathological significance in primary tongue squamous cell carcinoma (TSCC). Gene expression profiles of CBX3/HP1γ in TSCC from Oncomine database were analyzed. The expression of CBX3/HP1γ at protein level was measured using immunohistochemistry (IHC). The potential associations between CBX3/HP1γ expression and multiple clinicopathological parameters were estimated using the Chi square test. In addition, the effect of CBX3/HP1γ expression on patients' survival was further assessed by Kaplan-Meier and Cox regression analyses. The agreement of elevated CBX3/HP1γ expression was indicated in four datasets on the Oncomine database. Aberrant overexpression of CBX3/HP1γ was identified in TSCC tissues compared with cancer-adjacent normal tissue, which was significantly associated with cervical nodes metastasis (P=0.010) and clinical stage (P=0.025). Furthermore, patients with high CBX3/HP1γ expression exhibited a reduced survival compared with those with low expression (Log-rank test, P=0.004). Univariate and multivariate Cox regression analysis suggested that the expression status of CBX3/HP1γ could be regarded as an independent prognostic factor for TSCC patients (HR=2.461; 95% CI=1.128–5.370; P=0.024). The present study indicated that aberrant overexpression of Cbx3/HP1γ was associated with cervical nodes metastasis and unfavorable survival in TSCC. These findings suggest that CBX3/HP1γ may serve an important role in tongue tumorigenesis and may be a valuable candidate diagnostic and prognostic marker for TSCC patients.