A method of classifying a patient for eligibility for cancer therapy based on the presence or absence of splicing variants in a sample of the patient's cancer tissue. Also, a method of screening cancer therapies for efficacy against splicing variants. More specifically, the methods relate to novel splicing variants of genes associated with cancer risk and survival, particularly splicing variants of PIK3CD, FGFR3, TSC2, RASGRP2, ITGA4, MET, NF1 and BAK1. Also more specifically, the methods relate to classifying a patient for eligibility for cancer therapy involving the use of GS-1101.