Of interest, the analysis for the distributions of poly(A) reads showed switching of distal stop codon in clinical samples may indicate cancer cells prefer to use the shorten length of transcripts for both FGF2 and MAP4K4 when comparing to normal cells, and the knocking down of CSTF2 expression in H460 cells could lead to changes of transcript lengths of these genes according to the detected numbers and sites of poly(A) reads (Additional file 2: Fig. S1). Here, CSTF2 is linked to cancer.