HOXA13 and small cell lung carcinoma: To determine the clinical relevance of the HOTTIP/HOXA13 axis in SCLC, immunohistochemistry (IHC) method was used to detect HOXA13 expression in SCLC tissues and indicated that, only 3 of 60 cases were designated a score of 0 (negative staining), and higher staining intensity of HOXA13 may be correlated with extensive disease stage, poorer chemotherapy response, shorter median survival time, and poorer prognosis of SCLC patients (Supplementary Table 2, Figs. 5h, i).