Placental growth factor (PLGF), c‐MYC, and microRNA‐19a (miR‐19a) form an axis in gallbladder cancer (GBC). A, Quantitative RT‐PCR analysis of c‐MYC levels in PLGF siRNA‐treated (si‐1 and si‐2) NOZ cells. ***P < .001. B, Quantitative RT‐PCR analysis of c‐MYC levels in exogenous PLGF‐treated GBC‐SD cells. ***P < .001. C, Quantitative RT‐PCR and Western blot analysis of c‐MYC in NOZ and GBC‐SD cells transfected with c‐MYC siRNA or negative control siRNA (si‐NC). ***P < .001. D, Quantitative RT‐PCR analysis of miR‐19a levels in NOZ and GBC cells transfected with c‐MYC siRNA or si‐NC. ***P < .001. E, Quantitative RT‐PCR analysis of miR‐19a levels in NOZ and GBC cells treated with 100 ng/mL PLGF for 0, 24, and 48 h. ***P < .001. F, Quantitative RT‐PCR analysis of miR‐19a levels in NOZ cells transfected with PLGF siRNA (si‐1 and si‐2) or si‐NC. **P < .01. G, Scatterplots of the relative expression levels of miR‐19a in 39 paired GBC tissues and their corresponding normal adjacent tissues (NAT). miR‐19a expression was calculated and expressed as the miR‐19a/U6 expression ratio (2−Δ
CT); P = .009. H, miR‐19a expression in GBC tissues and NATs from the same 39 patients (quantitative RT‐PCR) (U6 as the internal control; Wilcoxon matched‐pairs test). I, Kaplan–Meier overall survival curve of GBC patients based on miR‐19a expression; P = .0011. J, Correlation between the expression levels of PLGF and c‐MYC was determined using linear regression analysis and paired t‐test with the same samples used (P < .001, r = .4221, n = 39; Pearson's correlation). K, Correlation between PLGF expression levels and miR‐19a (P < .001, r = 1.065, n = 39; Pearson's correlation). L, Correlation between the expression levels of c‐MYC and miR‐19a (P = .0069, r = 1.033, n = 39; Pearson's correlation)