CD44 and cancer: Thirdly, the phenotype of our study was a heterogeneous aggregation of a variety of cancer types, and only for part of CD44 polymorphisms, a subgroup analysis based on cancer type was conducted, while for others, attributing to the limited number of studies for specific cancers, such as BC and CC, we were unable to validate the potential effects on these cancers homogeneous or not, which should be investigated in the future.