TMPRSS4 and non-small cell lung carcinoma: In contrast to the elevated transcript levels found in a majority of primary NSCLC tumor samples, only six out of sixteen cell lines tested expressed TMPRSS4 transcripts by qPCR and conventional RT-PCR analyses (Fig. 1B) under normal culture conditions and, in a separate study, the majority of cell lines positive for TMPRSS4 message were found to be negative for protein expression (Fig. 5).