Background: To investigate the relationship of p63 expression and p63 locus at chromosomal 3q27-q29 in non-small cell lung cancer (NSCLC).
Methods: Chromosomal imbalance in 30 cases of squamous cell carcinoma (SCC) and 40 cases of adenocarcinoma of the lung were evaluated by comparative genomic hybridization (CGH) technology. A tissue microarray of specimens from 122 primary NSCLC specimens was employed and used for immunohistochemical detection of p63 protein expression.
Results: p63 positivity was found in 54 (44.26%) cases of NSCLC. p63 immunostaining was observed in 51 (86.44%) of 59 SCC, whereas only one adenocarcinoma (1.67%) showed immunoreactivity. Immunopositivity was seen in 2 (66.66%) of 3 large cell lung cancer (LCLC). No correlation existed between p63 protein expression and the age of patient, sex, tumor grading, tumor metastasis, prognosis (P > 0.05). The CGH results revealed that the gain of chromosome 3q27-q29 was identified in 32 (48.57%) of 70 NSCLC samples tested. Overrepresentation was detected in 24 cases of 30 SCC. In 40 adenocarcinoma, only 8 cases showed chromosome gain at chromosomal 3q27-q29. The comparison of p63 immunostaining with chromosomal alteration of 3q27-q29 demonstrated that pronounced gain was detected in 23 (95.83%) cases of 24 SCC with p63 immunopositivity. One case of adenocarcinoma that was p63 positive showed a chromosomal 3q27-q29 normal representation but not pronounced gain.
Conclusions: The results suggest that p63 immuno-positivity correlates significantly with pronounced gains of the p63 locus at chromosomal 3q27-q29, and p63 gene amplification correlates with development and progression of lung SCC.