However, recent studies on its expression in extrapulmonary carcinomas have demonstrated that TTF-1 is not as specific for lung and thyroid carcinomas as was previously thought: positivity of this marker can be observed, although much less frequently, in some carcinomas arising in other organs, such as the ovaries, endometrium, colon, and breast, as well as in some tumors of the central nervous system. The gene discussed is TTF1; the disease is carcinoma.