STIM1 and Familial prostate cancer: We thus determined relative STIM and Orai expression levels in non-tumorous and tumorous tissue from 13 prostate cancer patients by qRT-PCR, from which 13 expressed detectable levels of STIM1, STIM2 and Orai1 and 11 detectable levels of Orai2 and Orai3 (see methods).