PCA3 and prostate cancer: Cluster 6 included PCA3, HPGD, and FABP5; the former produces a protein, which is a key prostate cancer biomarker in urine tests (Farha and Salami 2022), while the latter two genes have been implicated as metabolic regulators of prostate cancer (Senga et al. 2018, Wang et al. 2020).