Fig. 1.

HER3 overexpressed in lung cancer HCC827-derived tumorspheres. a HCC827-derived tumorspheres were cultured in serum-free RPMI-1640 medium with the addition of EGF, bFGF, insulin, and heparin and incubated for 7 days. Tumorspheres were approximately 100 μm in diameter, measured using an inverted microscope. Bar scale, 100 μm. b HER3 (ERBB3) was detected through Western blot, which revealed high expression in HCC827-derived tumorspheres. c RNAseq was used to search and validate differential genes involved in the formation of tumorspheres. The results validated the overexpression of KIT and ERBB3 (a detailed gene list shown in Additional file 1: Table S1), d and ERBB2 and CD133 (PROM1), a marker for cancer stemness, also increased. e To validate that the expression of ERBB2 and ERBB3 were associated with the patient survival rate, a Kaplan Meier plotter was used (http://kmplot.com/analysis/). Results revealed that higher ERBB2 and ERBB3 individually reduced the probability of survival in patients with lung adenocarcinoma (p = 0.00013 for ERBB2 and p = 0.013 for ERBB3)