To evaluate the expression frequency of CT antigens in SCLC cell lines, six SCLC cell lines above were co-typed for expression of LAGE-1, MAGE-1, MAGE-3 MAGE-4, MAGE-10, CT-7, NY-ESO-1, NY-SAR-35, SSX1, SSX2, SSX4, KP-LU-35, SCP-1, and NY-TLU-57 by RT-PCR. This evidence concerns the gene SSX1 and small cell lung carcinoma.