MTAP（methylthioadenosine phosphorylase），癌症关联基因，基因ID：4507，该基因编码一种在多胺代谢中起主要作用的酶，对腺嘌呤和蛋氨酸的修复都很重要。编码酶在许多癌症中缺乏，因为这个基因和抑癌基因p16被共同删除。已经描述了该基因的多个选择性剪接转录变体，但它们的全长性质仍然未知。This gene encodes an enzyme that plays a major role in polyamine metabolism and is important for the salvage of both adenine and methionine. The encoded enzyme is deficient in many cancers because this gene and the tumor suppressor p16 gene are co-deleted. Multiple alternatively spliced transcript variants have been described for this gene， but their full-length natures remain unknown.关联癌症：乳腺癌。