Prognostic value of mutant p53, Ki-67, and TTF-1 and their correlation with EGFR mutation in patients with non-small cell lung cancer.

Abstract

The clinical characteristics of non-small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) mutation have been well studied. However, the correlation of EGFR mutation with mutant p53, Ki-67, and thyroid transcription factor 1 (TTF-1) and their prognostic value remain indistinct. Clinical and pathological characteristics and overall survival were analysed retrospectively in 523 surgically resected NSCLC patients. The expression levels of p53, Ki-67, and TTF-1 protein were detected by immunohistochemistry, and an amplification refractory mutation system was used to access the status of EGFR mutations. Of 523 patients with surgically resected NSCLC, 210 patients (38.4%) harboured EGFR mutations. Compared to the EGFR wild-type lung cancer, mutated EGFR harboured significantly increased mutant p53-positive or TTF-1-positive tumors (P<0.001 and<0.001, respectively). Former or current smokers, pathological stage and mutant p53-or TTF-1-positive status were independent predictors of EGFR mutation (P=0.001, 0.014, 0.014 and <0.001, respectively). Patients with p53 under expression had significantly better overall survival in the whole cohort and wild-type EGFR cohort (P=0.0010 and 0.0020, respectively) as well as in Ki-67-negative and TTF-1-positive patients (P<0.0001 and 0.0009, and P<0.0001 and 0.0004, respectively). Interestingly, in patients harbouring EGFR mutations, p53-under expression and Ki-67-negative cases still had better survival than positive cases, whereas there was no obvious difference between TTF-1-negative and TTF-1-positive cases (P=0.0198, 0.0068 and 0.3684, respectively). Finally, in NSCLC patients with wild-type EGFR, positive Ki-67 expression was the independent predictor for the worst survival (P=0.022). The expression levels of mutant p53, Ki-67, and TTF-1 were correlated with EGFR mutation. High expression of mutant p53 and Ki-67 correlated with poor survival in the entire cohort, EGFR mutation or wild-type cohort. In addition, Ki-67 might have an impact on the prognosis for patients with NSCLC with wild-type EGFR.