[Alternative splicing of insulin receptor mRNA in cancer and type 2 diabetes mellitus: a review].

The insulin receptor exists in two isoforms that result from alternative splicing of exon 11 in the primary transcript. The two isoforms have different affinities for insulin and insulin-like growth factors, and mediate different biological actions by different intracellular pathways. Differential expression of the two isoforms not only might contribute to insulin resistance in type 2 diabetes mellitus, but also play an important role in the pathogenesis of cancer. Alternative splicing can be regulated by metabolic and hormonal factors, such as hyperinsulinemia and hyperglycemia, but the precise mechanism is unknown. It has also been demonstrated that there are certain important nucleotide sequences in insulin receptor gene that can influence alternative splicing.