We further observed diminished and disorganised stroma in tumours driven by combined loss of Pten and Arid1a. To our knowledge, the Pb-Cre;Ptenfl/flArid1afl/fl mouse model exhibited the most rapid tumour development to clinical endpoint of any published prostate cancer GEMM, with a hyperproliferative and locally invasive cancer [52]. The gene discussed is ARID1A; the disease is prostate cancer.