Propranolol is a widely-known beta-blocker approved for treating infantile hemangiomas (IH). The mechanisms behind the spectacular IH involution after propranolol treatment remain unclear. Recently, there is strong evidence of overexpression of numerous angiogenic factors in IH tissues, and it is reported that propranolol influences their pathways. However, a number of MMPs studies is highly limited. Here, for the first time, we propose a comprehensive approach by analyzing the expression levels of metalloproteinases-2/9 (MMPs-2/9) and tissue metalloproteinase inhibitor-2 (TIMP-2) in vivo on both, molecular and immunohistochemical levels, and in both, IH tissues and in the serum of IH patients, and relates the obtained results to the tumor's biology and systemic propranolol treatment.
Material and methods: MMPs-2/9 and TIMP-2 were analyzed in 71 IH tissue samples using immunohistochemistry and real-time PCR, and in 50 serum samples of IH patients by ELISA.
Results: Significantly lower MMPs-2/9 and higher TIMP-2 levels were observed in IH tissues on the mRNA level as well as lower serum MMP-2 concentration among the treated individuals.
Conclusion: MMPs-2/9 and TIMP-2 are both involved in the biology of IH and the propranolol pathways enabling their antiangiogenic properties. The most reliable method of IH examination appears to be direct MMPs-2/9 mRNA evaluation in tumor tissue; and MMP-2 evaluation in patients' serum is a valuable complement to it. Tissue and serum mRNA MMPs assessment may represent a suitable novel biomarker identifying tumor progression and involution processes with potential clinical impact in IH as well as in cancer disease.
Keywords: Cancer; Infantile hemangioma; Involution; Metalloproteinases; Propranolol.
Copyright © 2017 Elsevier GmbH. All rights reserved.