PIWIL1 and cancer: Alternatively, this points to a more complex interplay between TEX19 and PIWIL1 in SW480 cancer cells, possibly indicating that TEX19 and PIWIL1 have opposing and independent roles in regulating TE transcripts (for example, TEX19 positively regulates HERVK pro, whereas PIWIL1 negatively regulates HERVK pro transcripts).