The cannabinoid receptors belong to the G protein-coupled receptor superfamily
and are integral part of the endocannabinoid system. Two main types of
cannabinoid receptors are known: cannabinoid receptor 1 (CB1) and cannabinoid
receptor 2 (CB2). In the last few years, great attention has been paid to the
immunohistochemical evaluation of CB1 and CB2 expression in various types of
tumors, including women’s cancers, for the alleged anticancer properties of
cannabinoids. Today, in the modern era of precision oncology, monoclonal
antibodies for the immunohistochemical evaluation of CB1 and CB2 expression are
available on the market; therefore, our recommendation is to submit preliminary
the formalin-fixed, paraffin-embedded, bioptic or surgical specimen of neoplastic
tissue, containing at least 100 tumor cells and coming from the selected patient
with no history of cannabis abuse, to predictive immunohistochemistry, before
undertaking any cannabinoid-based therapeutic attempt, in association with
conventional anticancer treatments or when the most advanced care is failing. The
receptor expression is determined through a ‘tumor proportion score’ (TPS), which
represents the percentage of viable neoplastic cells showing partial or complete
membrane staining. By exploiting a methodology analogous to that applied for
PD-L1 (programmed death-ligand 1) testing on cancer tissues, the specimen can be
considered to have a high CB1 and/or CB2 expression if TPS
