Because the presence of medullary thyroid cancer in multiple endocrine neoplasia type 2 (MEN2) syndrome might involve screening of families, in order to evaluate the presence of thyroid nodules, proto-oncogene RET mutations, and serologic calcitonin values, we considered that the respective epidemiology was in fact influenced by direct medical intervention. Here, CALCA is linked to medullary thyroid gland carcinoma.