The present invention provides in vitro methods for detecting, grading or prognosticating cancer, in particular prostate cancer. The invention further provides isolated polynucleotides suitable for reducing or inhibiting the expression of protein kinase C beta I and/or II and/or alpha (and consequently the levels of histone H3 phosphorylated at threonine 6, histone H3 monomethylated at lysine 4, histone H3 dimethylated at lysine 4, histone H3 trimethylated at lysine 4) and further relates to pharmaceutical compositions comprising said polynucleotides for the treatment or prevention of cancer, in particular prostate cancer.