A method of assessing likelihood of a patient having a prostate tumour benefiting from prostate cancer treatment, the method comprising: obtaining a sample of the prostate tumour or an extract thereof having message RNA therein of the patient; determining a gene expression profile of the sample for genes of each of three gene marker sets; and, comparing the gene expression profiles of the sample to standardized "good" and "bad" profiles of each respective gene marker set to determine whether each of the gene expression profiles predicts that the tumour is "good" or "bad", wherein if all three marker sets predict that the tumour is "good" then the patient is predicted to be at low-risk and would not likely benefit from prostate cancer treatment; if all three marker sets predict that the tumour is "bad" then the patient is predicted to be at high-risk and would likely benefit from prostate cancer treatment; and if one or two of the marker sets predict that the tumour is "good" or one or two of the marker sets predict that the tumour is "bad" then the patient is predicted to be at intermediate-risk and may or may not benefit from prostate cancer treatment, and wherein the gene marker sets are Set 1, Set 2 and Set 3, where Set 1 consists of apoptosis-related genes as follows: Gene EntrezGene ID Full Name of Gene COL4A3 1285 type IV collagen BIRC5 332 baculoviral IAP repeat containing 5 TOP2A 7153 topoisomerase II alpha CDC2 983 cyclin-dependent kinase 1 NRAS 4893 neuroblastoma RAS viral (v-ras) oncogene homolog GAS1 2619 growth arrest-specific 1 LIG4 3981 ligase IV, DNA, ATP-dependent OSM 5008 oncostatin M PML 5371 promyelocytic leukemia TP53 7157 tumour protein p53 NF1 4763 neurofibromin 1 SIAH1 6477 seven in absentia homolog 1 (Drosophila) MALT1 10892 mucosa associated lymphoid tissue lymphoma translocation gene 1 KIT 3815 v-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog RHOA 387 ras homolog gene family, member A ESR1 2099 estrogen receptor 1 RARB 5915 retinoic acid receptor, beta VAV1 7409 vav 1 guanine nucleotide exchange factor WRN 7486 Werner syndrome, RecQ helicase-like TNFRSF10A 8797 tumour necrosis factor receptor superfamily, member 10a RIPK1 8737 receptor (TNFRSF)-interacting serine-threonine kinase 1 ABL1 25 c-abl oncogene 1, non-receptor tyrosine kinase TERT 7015 telomerase reverse transcriptase GLI3 2737 GLI family zinc finger 3 JUN 3725 jun proto-oncogene NFKBIA 4792 nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha LCK 3932 lymphocyte-specific protein tyrosine kinase CASP3 836 caspase 3, apoptosis-related cysteine peptidase E2F2 1870 E2F transcription factor 2 LTA 4049 lymphotoxin alpha (TNF superfamily, member 1) Set 2 consists of cell cycle-related genes as follows: Gene Name EntrezGene ID Description BCL2 596 B-cell CLL/lymphoma 2 RAD51 5888 RAD51 homolog (RecA homolog, E. coli) (S. cerevisiae) CDKN2B 1030 cyclin-dependent kinase inhibitor 2B (p15, inhibits CDK4) GML 2765 glycosylphosphatidylinositol anchored molecule like protein E2F1 1869 E2F transcription factor 1 IKZF1 10320 IKAROS family zinc finger 1 (Ikaros) BLM 641 Bloom syndrome, RecQ helicase-like ABL1 25 c-abl oncogene 1, non-receptor tyrosine kinase LIG4 3981 ligase IV, DNA, ATP-dependent CCNA2 890 cyclin A2 NUMA1 4926 nuclear mitotic apparatus protein 1 CCNC 892 cyclin C RBL2 5934 retinoblastoma-like 2 LTA 4049 lymphotoxin alpha (TNF superfamily, member 1) ERCC2 2068 excision repair cross-complementing rodent repair deficiency, complementation group 2 CASP3 836 caspase 3, apoptosis-related cysteine peptidase TP53 7157 tumour protein p53 RAD54L 8438 RAD54-like (S. cerevisiae) CCND3 896 cyclin D3 WEE1 7465 WEE1 homolog (S. pombe) BIRC5 332 baculoviral IAP repeat containing 5 HDAC1 3065 histone deacetylase 1 Set 3 consists of response to external stimulus-related genes as follows: Gene Name EntrezGene ID Description COL4A3 1285 Type IV collagen TOP2A 7153 topoisomerase II alpha CDC2 983 cyclin-dependent kinase 1 LYN 4067 v-yes-1 Yamaguchi sarcoma viral related oncogene homolog PXN 5829 paxillin NTRK3 4916 neurotrophic tyrosine kinase, receptor, type 3 PDGFRA 5156 platelet-derived growth factor receptor, alpha polypeptide NRAS 4893 neuroblastoma RAS viral (v-ras) oncogene homolog CHEK1 1111 CHK1 checkpoint homolog (S. pombe) PARP1 142 poly (ADP-ribose) polymerase 1 KIT 3815 v-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog TGFBR3 7049 transforming growth factor, beta receptor III CCNA2 890 cyclin A2 NF1 4763 neurofibromin 1 MAPK10 5602 mitogen-activated protein kinase 10 CD9 928 CD9 molecule ESR1 2099 estrogen receptor 1 FRAP1 2475 mechanistic target of rapamycin (serine/threonine kinase) (MTOR) PML 5371 promyelocytic leukemia ABL1 25 c-abl oncogene 1, non-receptor tyrosine kinase TP53 7157 tumour protein p53 LIG4 3981 ligase IV, DNA, ATP-dependent WEE1 7465 WEE1 homolog (S. pombe SYK 6850 spleen tyrosine kinase MALT1 10892 mucosa associated lymphoid tissue lymphoma translocation gene 1 PTCH1 5727 patched 1 CASP3 836 caspase 3, apoptosis-related cysteine peptidase BLM 641 Bloom syndrome, RecQ helicase-like FYN 2534 FYN oncogene related to SRC, FGR, YES WRN 7486 Werner syndrome, RecQ helicase-like