Matching the treatment group with age at surgery revealed no significant differences in the number of SOX18+, RBPJ+, or SOX18+RBPJ+ cells in the age-matched cohort of 13 IH specimens from patients who received no pharmacologic therapy and 13 IH specimens from patients who received propranolol therapy (Supplemental Figure 6). This evidence concerns the gene SOX18 and isolated hemihyperplasia.