In fibroblasts, Smads appear to function as inducible DNA-binding transcription factors [25], as confirmed by the research conducted by Zimin Wang et al. wherein suppression of Smad3 expression in human keloid fibroblasts by RNA interface (RNAi) technology revealed that, in comparison with the control, mRNA levels of types I and III proCollagen were also significantly and uniquely decreased following reduction of Smad3 by siRNA [26]. Here, SMAD3 is linked to keloid.