PRKCD and breast cancer: Additionally, natural indolocarbazole analogues obtained from marine sediment strains of S. fradiae were found to inhibit pancreatic cancer (PC) tumor growth through selective inhibition of PKCθ/δ, a known tumor promoter, with its increased expression serving as a negative prognostic indicator for human breast cancer; thus, it is speculated that this compound may also inhibit breast cancer growth [12].