CHGA and neuroendocrine neoplasm: Fittingly, a positive correlation was found between the IRS values of GPR68 and those of typical markers for neuroendocrine tumours, known to be associated with a good prognosis [17,18] (chromogranin A (rsp = 0.137, p = 0.028), somatostatin receptor (SST) 2A (rsp = 0.201, p = 0.001), SST3 (rsp = 0.133, p = 0.032), and SST5 (rsp = 0.148, p = 0.028)).