Consistent with ASCL1 and FOXA2 having distinct roles, immunofluorescence (IF) analysis showed that ASCL1 and PROX1 were expressed in both never-met SCLC and in met-associated primary SCLC, whereas FOXA2 was enriched only in met-associated SCLC (Fig. 6a). The gene discussed is PROX1; the disease is small cell lung carcinoma.