KRT5 and thyroid gland papillary carcinoma: In immunohistochemistry, breast origin markers GCDFP-15 and GATA-3 were frequently strongly positively expressed, thyroid papillary carcinoma markers TTF-1 and TG were negative, the majority of TCCRP had a Ki67 proliferative index of less than 10% indicating a better prognosis, CK5/6 was usually positive, and p63 was usually negative suggesting a certain degree of aggressiveness.