A method of diagnosing whether a human subject has a prostate carcinoma, comprising: a) providing a sample containing prostate cells from the subject; b) hybridizing a set of at least four chromosome-specific probes to the prostate cells, wherein each chromosome-specific probe has a detectable label and a nucleotide sequence that is complementary to a repetitive genomic sequence of a specific human chromosome, and is specific for a different human chromosome; wherein the set of chromosome-specific probes includes i. a chromosome-specific probe for human chromosome 6, a chromosome-specific probe for human chromosome 8, a chromosome-specific probe for human chromosome 10, and a chromosome-specific probe for human chromosome Y; or, ii. a chromosome-specific probe for human chromosome 7, a chromosome-specific probe for human chromosome 16, a chromosome-specific probe for human chromosome 18, and a chromosome-specific probe for human chromosome 20; c) removing unhybridized probes; d) detecting the labels on chromosome-specific probes that have hybridized to the prostate cells; and e) determining whether the prostate cells include prostate cells that are polysomic for at least four chromosomes selected from the group consisting of human chromosome 6, human chromosome 8, human chromosome 10, and human chromosome Y; or human chromosome 7, human chromosome 16, human chromosome 18, and human chromosome 20, wherein the presence of prostate cells that are polysomic for human chromosome 6, human chromosome 8, human chromosome 10, or human chromosome Y; or human chromosome 7, human chromosome 16, human chromosome 18, or human chromosome 20 indicates that the subject has a prostate carcinoma. a) providing a sample containing prostate cells from the subject; b) hybridizing a set of at least four chromosome-specific probes to the prostate cells, wherein each chromosome-specific probe has a detectable label and a nucleotide sequence that is complementary to a repetitive genomic sequence of a specific human chromosome, and is specific for a different human chromosome; wherein the set of chromosome-specific probes includes i. a chromosome-specific probe for human chromosome 6, a chromosome-specific probe for human chromosome 8, a chromosome-specific probe for human chromosome 10, and a chromosome-specific probe for human chromosome Y; or, ii. a chromosome-specific probe for human chromosome 7, a chromosome-specific probe for human chromosome 16, a chromosome-specific probe for human chromosome 18, and a chromosome-specific probe for human chromosome 20; i. a chromosome-specific probe for human chromosome 6, a chromosome-specific probe for human chromosome 8, a chromosome-specific probe for human chromosome 10, and a chromosome-specific probe for human chromosome Y; or, ii. a chromosome-specific probe for human chromosome 7, a chromosome-specific probe for human chromosome 16, a chromosome-specific probe for human chromosome 18, and a chromosome-specific probe for human chromosome 20; c) removing unhybridized probes; d) detecting the labels on chromosome-specific probes that have hybridized to the prostate cells; and e) determining whether the prostate cells include prostate cells that are polysomic for at least four chromosomes selected from the group consisting of human chromosome 6, human chromosome 8, human chromosome 10, and human chromosome Y; or human chromosome 7, human chromosome 16, human chromosome 18, and human chromosome 20,