Considering the stoichiometry of TGF-β receptor complexes in heterozygous knockout mice (Tgfbr1+/− and Tgfbr2+/−) and MSSE patients with HI-type mutations, the existing TGF-β receptor complexes are all intact, and expression levels are theoretically one-half of the wild-type phenotype. This evidence concerns the gene TGFBR1 and multiple self-healing squamous epithelioma.