Tumor-related gene expression levels in pulmonary pleomorphic carcinoma

Takeshi Oyaizu, Yuji Matsumura, Satoru Kobayashi, Tetsu Sado, Hiromi Ishihama, Masayuki Chida

Pulmonary pleomorphic carcinoma (PPC) is a rare type of non-small-cell lung cancer that belongs to the family of sarcomatoid carcinomas and is associated with poor prognosis. We investigated the expressions of tumor-related genes in resected PPC specimens. Specimens resected from patients with PPC from July 2006 through April 2012 were investigated. Tumor segments were collected from the specimens by micro-dissection to extract mRNA, then RT-PCR was performed according to Dannenberg's tumor profile method for semi-quantitation of tumor-related gene mRNA. To compare with other types of lung cancer, data from stage-matched adenocarcinoma (AC) and squamous cell carcinoma (SCC) cases in our database were also examined. The gene expression levels of thymidylate synthase were significantly higher in PPC and SCC as compared to the AC specimens (p < 0.001). The levels of dihydropyrimidine dehydrogenase and thymidine phosphorylase mRNA in PPC showed a similar tendency to those in SCC, in contrast to AC. Furthermore, the expression level of excision repair cross-complementation group 1 mRNA in PPC specimens was similar to that reported in NSCLC, while the level of vascular endothelial growth factor (VEGF) expression was higher as compared to that reported for colorectal cancer. Although gene expression of tumor cannot be directly correlated to its sensitivity for anti-cancer drugs, it is likely that PPC tumors are not sensitive to anti-metabolic drugs. Anti-VEGF therapy may be a candidate for PPC, while cisplatin also remains a viable option.