Therefore, CD44 gene may be one of the high-penetrance genes that affect breast cancer susceptibility.[21] The human CD44 gene is located on the short arm of chromosome 11 (11p13) and consists of 20 highly conserved exon and introns of different lengths.[22] More and more studies have focused on the impact of CD44 gene ssingle-nucleotide polymorphisms on cancer risk. The gene discussed is CD44; the disease is cancer.