To study the biological significance of increased FABP9 in highly malignant prostate cancer cells, knockdown of FABP9 mRNA was performed via RNAi in highly-expressing PC3-M cells to establish highly- and moderately-suppressed transfectant cell lines, named PC3M-FABP9-siH and PC3M-FABP9-siM, respectively. This evidence concerns the gene FABP9 and Familial prostate cancer.