Complex sentence: The OncomiR-1 line was the first functional evidence of miRNA, or any noncoding RNA, effectively acting as mammalian oncogenes as it was proven that miR-17--19b, a portion of the OncomiR-1 miRNA line, accelerated lympomagenesis in rats.
Split into simpler sentences: The OncomiR-1 line was the first functional evidence of miRNA, or any non-coding RNA (ncRNA), effectively acting as mammalian oncogenes. This was demonstrated by the observation that miR-17--19b, a portion of the OncomiR-1 miRNA line, accelerated lympomagenesis in rats.