Table 2 MMR gene mutations in rapid autopsy patients.

Autopsy patient*	Tumour site(s) tested by BROCA targeted sequencing	Mutation burden ^† (exome)	Hypermutated?	MSI	MMR gene mutation(s) ^‡
05–165*	Bone, adrenal, liver and lymph node	855	Yes	Yes	(1) MSH2-C2orf61 343 kb inversion
					(2) MSH2-KCNK12 74 kb inversion
					(3) MSH2-KCNK12 40 kb inversion
03–130	Lymph node	647	Yes	Yes	(1) MSH2 translocation splits the gene t(2;18)
					(2) MSH2 copy loss
					(3) MSH6 frameshift (c.2690del)
					(4) MSH6 copy loss
06–134	Kidney and lymph node	314	Yes	Yes	MLH1 homozygous copy loss
00–010	Prostate and liver	673	Yes	Yes	MSH2 frameshift (c.2364_2365insTACA)
05–123	Prostate and lymph node	807	Yes	Yes	(1) MSH2 frameshift (c.1124_1125insG)
					(2) MSH2 frameshift (c.1082del)
					(3) MLH1 frameshift (c.1310del), lymph node only
01–095	Liver and lymph node	149	No	No	None
05–144*	Bone, adrenal, liver and lymph node	57	No	No	(1) MSH2 exon 8–16 del
					(2) MSH6-TESC t(2;12)
05–214	Bone, liver and lymph node (two sites)	46	No	No	None
05–116	Bone, adrenal, liver and lung	47	No	No	None
00–029	Liver	37	No	No	None
00–090	Lymph node	69	No	No	None

MMR, mismatch repair; MSI, microsatellite instability.
^*Fifty total unique autopsy patients were assessed by exome sequencing (see Supplementary Table 1). Listed are a subset of cases that were followed up by targeted deep sequencing for MMR genes. Clinical data for this patient subset is provided in Supplementary Table 6. Patient-matched non-cancer tissue was tested in every case and did not exhibit MSI or MMR mutations. LuCaP 147 and 147CR are derived from autopsy patient 05–165. LuCaP 145.1 and 145.2 are derived from autopsy patient 05–144.
^†Number of protein altering somatic mutations by exome sequencing with removing of germline variants from matched-non-tumour samples.
^‡Mutations were detected at every tumour site unless otherwise indicated. Mosaic MSH6 frameshift mutations observed in a poly G tract in exon 5 (c.3261dup/del) and poly A tract in exon 7 (c.3573del) were detected in several hypermutated samples and are not included in the table because they are presumed to be due to MSI.

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