IFNG and small cell lung carcinoma: Nevertheless, the TAP-, Tsn-independent peptides were not provided when these tests were expanded to tumor cell lines generated from SCLC, which researchers demonstrated to be Tsn deficient in addition to TAP-negative. Pre-treating SCLC cells with IFN-γ might address this lack of presentation. Or, the TAP-, Tsn-independent peptides were effectively delivered by SCLC cells using an ER signal sequence that guided them into the ER.