Expression and Clinical Significance of ERCC1 and XPF in Human Hepatocellular Carcinoma

To investigate the correlation between the ERCC1 and XPF expression and the clinicopathological parameters of hepatocellular carcinoma (HCC) patients through assessment of the expression of the DNA repair genes ERCC1 and XPF.

ERCC1 and XPF mRNA expression in HCC (n= 177) and adjacent para-cancer tissues (n=21) were assessed by RT-PCR. The correlation between ERCC1 and XPF expression, clinicopathological features and HCC prognosis were compared.

ERCC1 expression in liver cancer tissues was significantly lower than that of adjacent tissues (9.5% (2/21) vs 38.1% (8/21); P<0.05). The positive expression rates of XPF in liver cancer tissues was lower than that of adjacent tissues (14.3% (3/21) vs 71.4% (15/21); P<0.05). ERCC1 and XPF expression were associated with hepatic capsular invasion and microvascular invasion. HCC patients with hepatic capsular invasion and microvascular tumor embolus formation had significantly lower levels of ERCC1 and XPF mRNA than those without hepatic capsular invasion and microvascular tumor embolus formation (P<0.05). In addition, ERCC1 expression was associated with TNM staging of HCC. The expression of ERCC1 mRNA in patients with stage II and III HCC were lower than that of patients with stage I HCC (P<0.05). The low levels of ERCC1 and XPF mRNA significantly correlated with relapse-free survival times (RFS) in HCC patients. The median RFS of the low ERCC1 expression group and low XPF expression group were shorter than those of the high expression group (15.0 months vs 32.0 months, P<0.05) and (19.0 months vs 33.0 months, P<0.05). The decrease in XPF mRNA expression was significantly associated with the overall survival (OS) of HCC patients. The median OS in the low XPF expression group was shorter than that of the high expression group (46.0 months vs 78.0 months, P<0.05). However, no significant difference in OS between the low ERCC1 expression group and the high ERCC1 expression groups were observed (63.0 months vs 64.0 months, P>0.05). Multivariate analysis showed that tumor size and the extent of differentiation were independent factors affecting the RFS in HCC patients (P<0.05). The extent of differentiation and XPF were independent factors affecting the OS in HCC (P<0.05).

The expression in ERCC1 and XPF were low in HCC and associated with early relapse after HCC surgery. Low XPF expression may be a potential indicator of a high risk of death.