Immunohistochemical evaluation of myofibroblasts in odontogenic keratocyst, dentigerous cyst and different clinical variants of ameloblastoma: A comparative study

Abstract

Background: Odontogenic cysts and tumors exhibit varying degrees of aggressiveness in their
biological behavior. Odontogenic keratocyst (OKC), dentigerous cyst (DC), ameloblastoma are
most common odontogenic cysts and tumors to occur in the oral cavity. Myofibroblasts (MFs) in
the connective tissue stroma participate in the matrix degradation process by secreting matrix
metalloproteinase 2, transforming growth factor beta1 and may contribute to variation in their
biological behavior. Its activity is identified by alpha‑smooth muscle actin (α‑SMA) marker. With this
background, the present study aims to evaluate the frequency of MFs using α‑SMA to determine
the biological behavior of OKC, DC, and different clinical variants of ameloblastoma.
Materials and Methods: A retrospective study was carried out with total of 60 samples which
include 10 cases each of OKC, DC, 30 cases of different clinical variants of ameloblastomas and 10
normal mucosa taken as controls. All are stained immunohistochemically using α‑SMA and were
analyzed for the same. Comparison between more than 2 groups done by one way analysis of
variance test with the level of significance of P ≤ 0.0001, i.e., <0.05.
Results: Statistically significant difference in the mean number of MFs observed between certain
groups, with higher mean number in solid ameloblastoma (SA) (32.45) followed by OKC (28.79),
unicystic ameloblastoma (24.53), desmoplastic ameloblastoma (7.44), and DC (1.72).
Conclusion: Higher frequency of MFs noticed in SA, OKC which are key cells for connective
tissue remodeling by interacting with epithelial cells and other connective tissue cells to facilitate
progression of cysts and tumors thereby contributing to their biological behavior.
Key Words: Actins, ameloblastoma, matrix metalloproteinase 2, myofibroblasts, odontogenic
cysts, transforming growth factor beta1