NTRK3 and adenocarcinoma: We hypothesize that adenocarcinoma NOS, if classified appropriately, represents an assembly of molecularly distinct sub-entities, the scarcity of classic oncogene and tumor suppressor gene mutations pointing to the presence of major and characteristic genetic events, e.g. gene fusions as recently identified in the newly established entity mammary analogue secretory carcinoma of the salivary glands molecularly defined by an ETV6-NTRK3 fusion.