Cyclin D۱ as a Useful Marker for the Differentiation of Ewing’s Sarcoma from Rhabdomyosarcoma

Background: The main oncogenic action of CD۹۹ and cyclin D۱ biomarkers is referred to any mutation, amplification, and overexpression in cyclin D۱ coding gene, altering cell cycle progression as the main mechanism observed in a variety of tumors. A few studies attempted to detect the overexpression of cyclin D۱ and CD۹۹ and in certain types of tumors such as Ewing's sarcoma and rhabdomyosarcoma. The present study aimed to assess the prevalence of CD۹۹ and cyclin D۱ overexpression in these two types of tumors. We also described this overexpression according to the patients and tumor indicators. Methods: This cross-sectional survey was performed on ۳۰ consecutive patients with Ewing's sarcoma and ۲۲ patients with rhabdomyosarcoma and hospitalized in Shafa hospital in Tehran between ۲۰۰۹ and ۲۰۱۴. The assessment of CD۹۹ and cyclin D۱ markers was based on immunohistochemical assessment using the formalin fixed and paraffin embedded tissue samples of the two tumors. Results: Almost all Ewing's sarcomas had membranous patterns of CD۹۹ while this marker was negative in most patients with rhabdomyosarcoma. Therefore, detecting membranous CD۹۹ could specifically detect Ewing's sarcoma and distinguish it from rhabdomyosarcoma. Moreover, contrary to rhabdomyosarcoma which is accompanied with lower cyclin D۱ intensity, all Ewing's sarcomas were characterized by moderate to severe cyclin D۱ intensity. Similarly, almost all those with Ewing's sarcoma had diffuse cyclin D۱ extension; whereas, the pattern of cyclin D۱ extension in rhabdomyosarcoma was mostly negative or focal. Conclusion: The detection of CD۹۹ and cyclin D۱ overexpression and their intensity and extension patterns can specifically distinguish Ewing's sarcoma from rhabdomyosarcoma.