PRF1 and neoplasm: Interestingly, when tumor-related acidosis is extrapolated to other diseases and other microenvironments, such as the microenvironment generated by cryptococcoma (Cryptococcus gattii and Cryptococcus neoformans infections), the acidic pH in the center of the mass (analogous to the tumor mass) produces increased NK cell degranulation and perforin-mediated killing compared to pH 7.4 [104].