Fig. 1

Mutant KMT2C induces prostate intraepithelial neoplasia. a Schematic representation of the multi-subunit COMPASS (Complex Proteins Associated with Set1) complex containing KMT2C. KMT2C/D acts as a scaffold to bind multiple subunits unique to KMT2C or KMT2D containing COMPASS-like complexes (PAX-interacting protein 1 (PAXIP1), PAXIP1-associated glutamate-rich protein 1 (PAGR1), nuclear receptor coactivator 6 (NCOA6), lysine specific demethylase 6A (KDM6A)) as well as proteins common to all KMT2 complexes (WD repeat-containing protein 5 (WDR5), Retinoblastoma-binding protein 5 (RBBP5), Set1/Ash2 histone methyltransferase complex subunit ASH2 (ASH2L), Protein dpy-30 homolog (DPY30)). The SET domain located at the C-terminal end of the protein confers the methyltransferase activity needed to methylate lysine 3 on histone 4 (H3K4me1) at enhancer regions. b Spectrum of KMT2C mutations in the MSKCC/DFCI patient cohort comprised of 680 primary and 333 metastatic PCa samples. Data were retrieved from cBioPortal. Left panel: Top 10 most frequently mutated genes in this cohort. Right panel: Proportion of KMT2C alterations found in primary and metastatic PCa samples. Values within and above bars indicate alteration frequency of the respective mutation type and total percentage of altered samples, respectively. Samples with simultaneous mutations of more than one class are depicted with alternating stripes of both respective colours. c Scheme of the construct allowing for the conditional deletion of exon 57 and 58 within the SET domain of Kmt2c, which confers the methyltransferase activity, and the mutant transcript expressed specifically in prostate epithelial cells after Cre-mediated recombination controlled by the androgen-dependent probasin promoter (hereafter Kmt2c^SET∆/∆). d Weight of wild type and Kmt2c^SET∆/∆ prostates at 19 weeks p.p. (n = 18) e Representative pictures of PIN formation in a 19-week-old Kmt2c^SET∆/∆ prostate. Wild type prostate is shown as a control. Scale bars: 50 µm. f Percentage of wild type and Kmt2c^SET∆/∆ mice presenting with PIN at 19- and 90 weeks p.p. Number above the bar indicates PIN-positive/total number of analysed mice. (n ≥ 5) g-h Representative pictures of Ki-67 IHC analysis of wild type and Kmt2c^SET∆/∆ mouse prostate tissue at 19 weeks p.p. (n ≥ 9) (g) and associated quantification (h). Scale bars: 50 µm. Cells positive for Ki-67 were quantified using QuPath software. i-j Representative pictures of AR IHC analysis of wild type and Kmt2c^SET∆/∆ mouse prostate tissue at 19 weeks p.p. (n ≥ 9) (i) and associated quantification (j). Scale bars: 50 µm. Stains were semi-quantitatively analysed by a board-certified genitourinary pathologist. Arbitrary unit (AU) is a multiplication of percentage of positive cells and staining intensity (0, 1, 2, 3). (d, h, and j) Individual biological replicates are shown. Data are plotted as the mean ± standard deviation, and P values were determined by unpaired two-tailed Student’s t-tests