DNA aneuploidy, S-phase fraction and nuclear p53 positivity in non-small cell lung carcinoma

Surgical resection currently offers the best option for managing non-small cell lung carcinoma (NSCLC) but its efficiency is limited by subsequent tumor recurrence. We evaluated whether flow cytometric study and the p53 gene staining pattern may be useful in this respect.

We took biopsy samples of 40 patients with operable NSCLC to study the frequency of aneuploidy, proliferative activity, and alterations in the p53 tumor suppressor gene and compared them with clinicopathological parameters such as age, gender, smoking, histological type, tumor size, and degree of differentiation. To study DNA content, the nuclei were analyzed by flow cytometry using a FACS flow cytometer (Becton-Dickinson) equipped with an argon ion laser, with a propidium iodide excitation of 488 nm. We used the immunohistochemical technique for p53 analysis in samples of paraffin-embedded tissue corresponding to the same patients from whom fresh tissue was taken.

Nuclear p53 staining was detected in 66.7% of the samples; 69.4% of the cases revealed aneuploid DNA histograms and 59% presented with an S phase fraction of more than 12%. Comparison with clinicopathological parameters showed that p53 protein was associated significantly with histological classification (p = 0.04), gender (p = 0.01), and smoking (p = 0.04).

Immunodetection of p53 overexpression and DNA ploidy in the bronchial epithelium may be a useful tool in any future multifactorial analysis in such tumors for identifying previous lesions that may progress to malignancy.