PTH and neoplasm: In the context of primary GBC, M Takahashi et al. suggested that tumour-secreted PTHrP might induce hypercalcaemia [34], a proposition later confirmed by Y Watanabe et al. and M Yanagi et al., whereby serum PTHrP levels in both patients with primary gallbladder in the background of normal PTH and vitamin D levels [11,39].