Expression of p63 and CK5/6 in early-stage lung squamous cell carcinoma is not only an early diagnostic indicator but also correlates with a good prognosis.

Background: Non-small cell lung cancer (NSCLC) accounts for 80% of lung cancers, and lung squamous cell carcinoma (SQCC) is one of the main types. Advances in the treatment of lung SQCC are lacking when compared to lung adenocarcinoma. The main treatment for early-stage SQCC is surgery. However, factors affecting the efficacy of surgical treatments for early-stage lung SQCC remain unclear. In this study, we examined the significance of commonly used lung SQCC diagnostic markers p63, p40, and cytokeratin (CK)5/6 in prognosis.

Methods: Seventy-six cases of early-stage lung SQCC (N0) were obtained from our lung cancer database (January 2000 to December 2009). Tissue microarray and immunohistochemical (IHC) staining were used to detect the expression of p63, p40, and CK5/6. The effect of the expression level of each marker on patients' survival was examined.

Results: Sensitivity and specificity of each marker for detecting lung SQCC was 87.0% and 81.0% for p63, 75.9% and 97.9% for p40, and 78.9% and 97.7% for CK5/6. Survival rates of patients with high expression levels of p63 or CK5/6 or both were higher than in patients with low expression levels (P < 0.05). Expression levels of p40 had no effect on survival (P > 0.05). Multivariate analysis showed that high levels of p63 expression p63+CK5/6 co-expression were independent prognostic factors for good survival.

Conclusion: IHC staining detection of p63 and CK5/6 in specimens should be routinely performed in postoperative early-stage lung SQCC patients. Its significance lies not only in differential diagnosis, but also in determining prognosis.