Prognostic significance of p21 protein expression in patients with pulmonary squamous cell carcinoma following induction chemotherapy

Background: The prognostic value of p21 protein expression in lung cancer patients has been assessed. However, its significance in those with pulmonary squamous cell carcinoma following induction chemotherapy (IC) remains unclear. We studied on patients who did or did not undergo IC (NIC) to elucidate the prognostic value of p21 protein expression. Materials and Methods: p21 protein expression was assessed immunohistochemically and samples with greater than 10% positive tumor cells were considered positive. We then analyzed clinicalpathological features, including p53 protein expression and prognosis, in 43 patients who underwent IC group and 40 who did not IC (NIC) group. Results: Positive nuclear p21 samples were obtained from 17 (41.5%) patients in the in IC group and 22 (55.0%) in the NIC group. In the IC group, there was no significant correlation between the histological effectiveness of chemotherapy and p53 protein expression, whereas a significant correlation was observed between that and p21 protein expression (p=0.048). Further, the prognosis for p21-positive patients tended to be better (p=0.0506) than for p21-negative patients, and was significant (p=0.048) in patients with pathological stage (p-stage) II or III disease. Conclusion: Our findings suggest that p21 protein expression is a prognostic factor for primary patients with pulmonary squamous cell carcinoma following IC.