Malignant salivary gland tumors and cyclo-oxygenase-2: a histopathological and immunohistochemical analysis with implications on histogenesis.

The classification system for malignant salivary gland tumors (MST) is largely dependent on its histogenesis. The histogenesis is uncertain but the "bicellular theory of origin" has been accepted by most and states that malignant transformation of reserve cells from either the intercalated or excretory duct are responsible for the development of MST. Cyclooxygenase-2 (cox-2), a potential molecular marker for MST, was analyzed on a series (n=56) of MST with the aim of determining the morphological MST subtypes capable of cox-2 overexpression and correlating its expression with histogenesis.