An isolated nucleic acid molecule consisting of 10 to 50 nucleotides which specifically hybridizes to PCA3 RNA or DNA, wherein said nucleic acid molecule is, or is complementary to, a nucleotide sequence consisting of at least 10 consecutive nucleotides from PCA3 exon 1 (1–98 of SEQ ID NO:1 or 1–120 of SEQ ID NO:6), 2 (99–263 of SEQ ID NO:1 or 121–285 of SEQ ID NO:6), 3 (264–446 of SEQ ID NO:1 or 286–468 of SEQ ID NO:6), 4a (447–985 of SEQ ID NO:1 or 469–1007 of SEQ ID NO:6), 4b (986–2037 of SEQ ID NO:1 or 1008–2066 of SEQ ID NO:6), 4c (2067–2622 of SEQ ID NO:6), or 4d (2623–3582 of SEQ ID NO:6), and wherein said nucleic acid molecule does not specifically hybridize to nucleotides 511–985 of SEQ ID NO:1 or nucleotides 533–1007 of SEQ ID NO:6.