BACKGROUNDTo investigate the relationship of p63 expression and p63 locus at chromosomal 3q27-q29 in non-small cell lung cancer (NSCLC).

METHODSChromosomal 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.

RESULTSp63 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.

CONCLUSIONSThe 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.