IMPORTANCE: Propranolol hydrochloride has become the primary medical treatment 
for problematic infantile hemangioma; however, the expression of propranolol's 
target receptors during growth, involution, and treatment of hemangioma remains 
unclear.
OBJECTIVE: To measure and compare the expression of β1-, β2-, and β3-adrenergic 
receptors (ADBR1, ADBR2, and ADBR3, respectively) in proliferative (n = 10), 
involuted (n = 11), and propranolol-responsive (n = 12) hemangioma tissue.
DESIGN, SETTING, AND PARTICIPANTS: Infantile hemangioma specimens were harvested 
for molecular investigation. Messenger RNA (mRNA) expression of the ADBR1, 
ADBR2, and ADBR3 genes was detected by real-time polymerase chain reaction. 
Protein level expression was measured by Western blot and standardized with 
densitometry. A total of 33 specimens were collected from patients in a tertiary 
pediatric hospital who underwent excision of problematic hemangiomas. This study 
was conducted from January 18, 2011, to September 24, 2013, and data analysis 
was performed from February 25, 2015, to June 25, 2016.
RESULTS: Of the 33 patients included, 21 were female (64%). The mean (SD) 
patient age at the time of excision was 7 (2.5) months for the proliferative 
group lesions, 23.5 (10) months for the involuted group, and 16 (10) months for 
the propranolol group. The mean level of ADBR1 mRNA expression was significantly 
higher in proliferative hemangioma than in propranolol-responsive hemangioma 
(1.05 [0.56] vs 0.52 [0.36]; P = .01; 95% CI, 0.12-0.94). There was no 
difference in ADBR2 expression among the groups. Protein expression of ADBR3 was 
significantly higher in involuted (0.64 [0.12] vs 0.26 [0.04]; P < .01; 95% CI, 
0.26-0.49) and propranolol-responsive hemangioma (0.66 [0.31] vs 0.26 [0.04]; 
P = .01; 95% CI, 0.16-0.68) compared with proliferative hemangioma.
CONCLUSIONS AND RELEVANCE: These data demonstrate the variable expression of 
ADBR subtypes among infantile hemangiomas during growth, involution, and 
response to treatment. These findings may have clinical implications regarding 
the use of selective vs nonselective β-blockade.
LEVEL OF EVIDENCE: 2.