CD44 and breast cancer: Although it has been reported that HA-CD44 signaling promotes the progression of several cancers, such as breast cancer [25], colorectal carcinoma [17], fibrosarcoma [26], and glioblastoma multiforme [27], in this study we found that CD44 was overexpressed in both normal tissue and PTC tissue and overexpression of CD44 was not relevant to progression of PTC.