COL4A1 and leiomyoma: The mRNA expression was increased for collagen genes COL1A1 (2·72 ± 0·55-fold; P < 0·05) and COL4A1 (2·95 ± 0·37-fold; P < 0·05) in leiomyoma cells as compared to myometrial cells prior to treatment (Fig. 3).