Expression And Significance Of Rb/p21～(WAF1/CIP1) Gene Protein In Infantile Skin Hemangioma

Objective: To investigate the expression and significanceof Rb/p21WAF1CIP1 gene protein in different stage of infantile dermalhemangiomas,vascular malformation and to study the relationship betweenexpression of Rb/p21^WAF1/CIP1 and regression of hemangiomas.The resultsmight be expected to provide a new therapy mode for the clinicalmanagement of hemangiomas. Methods: Fifty-four infantile dermalhemangiomas specimens,twenty-two specimens of vascular malformationand corresponding clinical data were studied. All the patients withhemangiomas and vascular malformation were untreated before operation.The hemangiomas specimens were classified into two groups: Group Aconcluding 28 hemangiomas of proliferating phase, group B concluding 26hemangiomas of involuting phase. 10 normal skin tissues were selected ascontrol group. Rb/p21^WAF1/CIP1 and the proliferating cell nuclear antigen(PCNA) were examined in 54 hemangiomas,22 vascular malformationsand 10 normal skin tissues by streptavidin proxidaseimmunohistochemistry method (S-P). The apoptotic cells in different stagesof infantile dermal hemangiomas and vascular malformations weredetected by TUNEL assay. Results: The positive rates of Rb expression ingroup A,group B and vascular malformation group were 28.57%,76.92%and 18.18% respectively;the positive rates of p21^WAF1/CIP1 expression were21.43%, 65.38% and 22.73% respectively. The expression rate of Rb andp21^WAF1/CIP1 in involuting phase hemangiomas was higher than inproliferating phase hemangiomas,vascular malformations (P<0.05) and innormal skin tissues (P<0.01). The PCNA expression rate is 78.57% in theproliferating hemangiomas , 30.77% in involuting hemangiomas and18.18% in vascular malformations. The expression rate of PCNA inproliferating hemangiomas was significantly higher than in involutinghemangiomas and vascular malformations (P<0.05). Apoptotic cells weredetected seldom in proliferating hemangiomas(apoptotic index 2.268±0.714)and vascular malformations (apoptotic index 1.346±0.583), butapoptotic cells increased significantly in involuting hemangiomasspecimens(apoptotic index 23.697±11.756). Conclusions:It is suggestedthat Rb/p21WAF1/CP1 might play an important role in the converting ofhemangiomas from proliferating phase into involuting phase.Theincreased apoptosis during the natural life cycle of hemangioma may beinvolved in regression of hemangiomas. Rb/p21^WAF1/CIP1 expression isinvolved in involuting phase. The activation of Rb and/or p21^WAF1/CIP1 mayinduce apoptosis of endothelial cells, thus lead to the regression ofhemangioma. The detection of expression of PCNA may be helpful for theclassification of hemangioma.