CARS protein is associated with cell surface NIS protein among ER+ breast tumors. Cell surface NIS and CARS protein were probed by immunohistochemistry on another breast tumor TMA composed of 42 tumors of various histological subtypes and tumors were assigned a score of 0, 1+, 2+ and 3+ for each respective protein. Scores of 0 and 1+ were considered to be negative and scores of 2+ and 3+ were considered positive. (A) Positive and negative NIS and CARS immunostaining from two representative breast tumors are shown. (B) While there appeared to be a trend of over- or under-expression of CARS in all NIS positive and negative tumors, respectively, the correlation did not achieve statistical significance by Fisher's exact test (P > 0.05). (C) Interestingly, CARS protein significantly correlated with breast tumors of ER+ histological subtype but not tumors triple negative for ER, PR and Her-2/neu.