SLC3A2 and breast cancer: An increasing amount of research shows that LAT1/4F2hc is over-expressed in a variety of human tumor cell lines and tumor tissues, suggesting that LAT1/4F2hc is implicated in the growth and proliferation of multiple types of human tumor [1,2,5], including lung cancer [6,7], breast cancer [8], esophageal carcinoma [9], prostate cancer [10], uterine cervical carcinoma [11], ovarian cancer [12], thymic carcinoma [13], oral cancer [14], head and neck squamous cell carcinoma [15], metastatic tumor [16], and so forth.