EXPRESSION OF ALPHA-SMOOTH MUSCLE ACTIN IN ODONTOGENIC CYSTS AND TUMORS

Area of Science:

• Oral Pathology
• Oncology
• Immunohistochemistry

Background:

• Odontogenic cysts and tumors display varying degrees of aggressiveness.
• Myofibroblasts (MFs) at the invasion front are implicated in promoting tumor invasion.
• MFs are recognized for their importance in the biological behavior of odontogenic lesions.

Purpose of the Study:

• To immunohistochemically assess alpha-smooth muscle actin (α-SMA) expression in MFs within odontogenic cysts and tumors.
• To correlate α-SMA expression with the biological behavior of these lesions.

Main Methods:

• Archival tissues from 40 cases (10 each of odontogenic keratocysts, radicular cysts, dentigerous cysts, and ameloblastomas) were analyzed.
• Immunohistochemical analysis was performed to evaluate α-SMA expression and localization of MFs.
• Mean MF counts and patterns of arrangement were determined.

Main Results:

• Mean MF counts were highest in odontogenic keratocysts, followed by ameloblastomas, dentigerous cysts, and radicular cysts.
• α-SMA expression was weak in 50% of cases, moderate in 22.5%, and intense in 10%.
• MFs exhibited spindle, focal, or network patterns in 35%, 27.5%, and 20% of cases, respectively.

Conclusions:

• MFs demonstrate heterogeneous distribution and arrangement patterns within odontogenic lesions.
• α-SMA immunopositive cells confirm the presence of MFs in the stroma of these lesions.
• This heterogeneity provides evidence for the role of MFs in the biological behavior of odontogenic cysts and tumors.