Most cancer drugs interact with one of four main target classes: kinases, cell cycle proteins, transcription factors and tumor suppressors. Because Cylene Pharmaceuticals Inc.’s ribosomal RNA biogenesis inhibitors act downstream from those signaling pathways, the company believes its compounds will show activity in many more tumors than do marketed drugs. Last week, it raised $44 million in a series C round to take its lead RBI into Phase II trials.

President and CEO William Rice said that although ribosomes are present