Evidence for association of multi-exon skipping events with tumors

Alternative splicing (AS) has been shown to be frequently present in human tumors. Specifically, it has been observed in some experimental studies thatmulti-exon skipping (MES) events often appear in tumorous tissues. Prompted by this observation, we conducted a genomewide analysis of MES events to investigate their association with tumors. The results show that MES events are more likely associated with tumors than single-exon skipping (SES) and the degree of association increases with the number of skipped exons. Furthermore, MES events are found to be less conserved than their SES counterparts, which provides additional evidence for our results because disease-associated AS events should be eliminated during evolution. Interestingly, these differences still existed even after comparison of MES and SES events with similarlength skipped regions. These results demonstrate that MES events may be associated with tumors and suggest that MES isoforms might be useful in cancer diagnosis.