MUC1 and non-small cell lung carcinoma: Reverse transcription-polymerase chain reaction (RT-PCR) of tumor associated mRNA such as carcinoma embryonic antigen (CEA) mRNA [3] and mucin type 1 (MUC1) mRNAs [8] was also demonstrated having the potential to identify a small number of tumor cells in histologically negative LN from NSCLC patients.