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 genome-wide 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 num-ber of skipped exons.Furthermore,MES events are found to be less conserved than their SES counterparts,which provides additional evidence for our results because dis-ease-associated AS events should be eliminated during evolution.Interestingly,these differences still existed even after comparison of MES and SES events with similar-length skipped regions.These results demonstrate that MES events may be associated with tumors and suggest that MES isoforms might be useful in cancer diagnosis.