Immunohistochemical study of p53 in non-small cell lung cancer before and after preoperative chemotherapy

The purpose of the study was to assess the expression of p53 in non-small cell lung cancer (NSCLC) before and after treatment with cisplatin and vepeside (PE) and to define a relationship between p53 expression and responsiveness to chemotherapy prior to surgery. Material for study consisted of specimens obtained from neoplastic infiltrate before chemotherapy (biopsy material) and tumour specimens obtained after chemotherapy (surgical material). The study population was a group of 35 patients with stage IIIA NSCLC. p53 protein accumulation was detected by immunohistochemistry using antibodies against p53: NCL-p53 (clone BP-53-12) (Novocastra) on paraffin embedded specimens. p53 expression was found in 21 patients (60%) before and after chemotherapy. In 14 patients (40%) p53 negativity was seen both in biopsy and surgical material. The level of p53 staining after chemotherapy as compared with that before treatment changed from -53 to +34. There was a mean increase by 1.52, which appeared statistically accidental (p > 0.70). There was no significant relationship between p53 expression and responsiveness to chemotherapy (from p > 0.33 to p > 0.70) and between the magnitude of changes in p53 expression and response to chemotherapy (p > 0.39). There was also a very low correlation (r to 0.10; p > 0.50) between responsiveness to therapy and p53 negativity.