RNPC3 and cancer: To pursue this notion further, we inhibited the expression of RNPC3/65K beyond the equivalent of a 50% reduction in gene dosage by transfecting A549 cells with siRNAs designed to target RNPC3. We showed that a 70% reduction in RNPC3 mRNA expression impaired the integrity of minor splicing and produced a concomitant reduction in cancer cell growth.