This work is licensed under Creative Commons Attribution–NonCommercial International License
(CC BY-NC 4.0).
Background: Mucoepidermoid carcinoma (MEC) counts among the most frequent types of malignant salivary gland
neoplasms. Brandwein system classified MEC into low, intermediate and high grade as per histological pattern, but
this classification lacks the correlation with the genetic basis such as MicroRNA profile. This study aims to assess the
expression level of MicroRNA-21 (miR-21) and MicroRNA-22 (miR-22) in different grades of MEC.
Material And Methods: Formalin-fixed paraffin-embedded blocks of MEC were obtained from Oral and
Maxillofacial Pathology Department, Faculty of Dentistry, Cairo University and General Pathology Department,
Faculty of Medicine, Cairo University within the period of (2014-2023). Reverse transcription polymerase chain
reaction was applied to measure the expression level of miR-21 and miR-22.
Results: The high grade group showed significant upregulation in the level of expression of miR-21 and miR-22 in
comparison to all other groups. The levels of upregulation of low group and intermediate group were insignificant. A
significant strong positive relationship was recorded between the levels of expression of miR-21 and miR-22 in all the
assessed grades of MEC.
Conclusions: As the levels of miR-21 and miR-22 were significantly increased in the high grade-group, these
MicroRNAs could be possibly used as prognostic markers in cases of MEC.