Expression of CD44 splicing isoforms in lung cancers: dominant expression of CD44v8-10 in non-small cell lung carcinomas.

We examined CD44 isoform expression in 138 frozen tissue samples, which included primary lung carcinomas, adjacent non-tumorous lung tissues and benign lung diseases, by both reverse transcriptase polymerase chain reaction (RT-PCR) and immunohistochemical analyses. CD44v8-10 mRNA and protein were dominantly expressed in non-small cell lung carcinomas (NSCLC), while non-tumorous tissues principally expressed CD44s and small cell lung carcinomas (SCLC) expressed either CD44s or no detectable CD44. These results indicate that CD44v8-10 is the dominant splicing isoform in NSCLC and can be practically utilized as a diagnostic marker and therapeutical target in NSCLC.