IGF1 and pachyonychia congenita: Conversely, another study showed no significant change in serum PSA level or insulin-like growth factor axis, including IGF-1 and the IGF-1/IGFBP-3 ratio, in a randomized, double-blind, placebo-controlled trial of polyphenon E (800 mg/day for 3–6 weeks) in PC patients [88].