As shown in Table 1, on exposure to 10−8m ATRA concentration, the expression of TGF-β3 mRNA in leiomyoma cells was similar to myometrial cells (0·84 ± 0·12; P < 0·05), indicating that ATRA down-regulated the TGF-β3 expression and thus may indirectly affect the TGF-β pathway. Here, TGFB1 is linked to leiomyoma.