SST and breast cancer: More recently, Oliveira et al. examined the effects of somatostatin (SST) (a growth hormone inhibitory peptide that exists in two naturally occurring bioactive isoforms), cannabidiol (CBD), alone or with both SST and CBD, on receptor expression (CBR1 and CBR2, SSTR2 and SSTR5), cell proliferation and apoptosis, and associated downstream signaling pathways in MDA-MB-231 and MCF-7 breast cancer cells.