library_construction_protocol: One half of the prostate from GEMMs was utilized for scRNA-seq while the contralateral half was fixed in 10% buffered formalin and embedded in paraffin blocks and sliced into sections with a thickness of 10um thickness. dried at 42°C for 3 hrs and kept in a desiccator at room temperature overnight, before proceeding with the Visium CytAssist spatial protocol (guides CG000518, CG000520 and CG000495). Slides were deparaffinized, H&E stained and imaged using an EVOS M7000 Automated Imaging System (10x objective, 3.45µm/pixel -Thermo Fisher Scientific, CA). Slides were then de-coverslipped and tissues were hematoxylin destained, decrosslinked and hybridized overnight with the whole mouse transcriptome panel which contains pairs of specific probes for each targeted gene (PN-1000365). After hybridization, the probe pairs were ligated, the slides loaded on a Visium CytAssist instrument, ROIs adjusted and ligated probes transferred and captured on an 11 mm Visium CytAssist Spatial Gene Expression slide containing UMIs and barcoded oligos. Spatially barcoded libraries were generated and sequenced with paired-end dual-indexing (28 cycles Read 1, 10 cycles i7, 10 cycles i5, 90 cycles Read 2).