CSTF2 and cancer: This measure of global 3′ UTR length was significantly positively correlated with PABPN1 expression in 28 of 30 cancer subtypes and significantly negatively correlated with CSTF2 expression in 21 of 30 cancer subtypes, consistent with PABPN1 and CSTF2’s known roles as a repressor or activator of proximal poly(A) site usage, respectively (Supplementary Fig. 1D–I)5–7.