SFRP4 and benign prostatic hyperplasia: Similarly, the pyramided lines BPH6 + BPH12 PYL and BPH3 + BPH27 PYL exhibited greater resistance levels in bulk seedling tests than monogenic lines with each of the genes present alone [14,55], and BPH17 + BPH21 PYL had greater resistance against BPH in the Philippines than lines with either gene alone [57].