C1S（complement C1s），癌症关联基因，基因ID：716，这个基因编码一种丝氨酸蛋白酶，它是人类补体亚组分C1的主要组成部分C1s与另外两个补体成分C1r和C1q相结合，以产生血清补体系统的第一个成分该基因缺陷是选择性c1s缺乏的原因。〔RefSeq，2009〕This gene encodes a serine protease， which is a major constituent of the human complement subcomponent C1. C1s associates with two other complement components C1r and C1q in order to yield the first component of the serum complement system. Defects in this gene are the cause of selective C1s deficiency. [provided by RefSeq， Mar 2009]。