Enhanced levels of insulin-like growth factor messenger RNA in human colon carcinomas and liposarcomas.
The insulin-like growth factors I and II (IGF-I and -II) are proteins which stimulate cell proliferation and are important in normal human growth and development. They are coded for by separate genes and bind to specific cell surface receptors, eliciting a mitogenic response. IGFs are secreted by several cell lines derived from adult tumors. We have examined a number of human adult tumors for IGF messenger RNA (mRNA) expression and found IGF-II mRNA levels were consistently elevated in two types, colon carcinoma and liposarcoma. Adult colonic mucosa contains low levels of IGF-I and -II mRNA while several colon tumors, particularly of rectal and rectosigmoid origin, contained significantly elevated levels of IGF-II message. Over 90% of liposarcomas examined contained greatly elevated levels of IGF-II mRNA while control tissue (adipose) contained very low or undetectable IGF mRNA levels. Many of these tumors also contained elevated IGF-I mRNA levels. Northern analysis of these RNAs revealed differences in the abundance and sizes of IGF transcripts compared to other normal and malignant tissues known to express IGF.
D002277:Carcinoma / Q000032:analysis*; D003110:Colonic Neoplasms / Q000032:analysis*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000235:genetics; D007335:Insulin-Like Growth Factor II / Q000235:genetics; D008080:Liposarcoma / Q000032:analysis*; D009693:Nucleic Acid Hybridization; D012333:RNA, Messenger / Q000032:analysis*; D013002:Somatomedins / Q000235:genetics*; D014158:Transcription, Genetic
D012333:RNA, Messenger; D013002:Somatomedins; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II