Diagnostic utility of immunohistochemical expressions of IMP3 versus DOG1 and p63 in salivary gland tumors

Abstract

Objective: The diverse site of origin and classification complexity of salivary glands tumors increase difficulties in their diagnosis. This study aimed to evaluate the specificity and diagnostic ability of immunohistochemical expressions of IMP3 versus DOG1 and p63 in cases of such tumors. Material and Method: Thirty paraffin-embedded salivary gland tumors were obtained from the Pathology Department Archive. Their diagnosis was confirmed. The specimens were then re-classified and evaluated using the IMP3, DOG1 and p63 immunohistochemical markers. Results: There were 8 pleomorphic adenoma (PA), 12 mucoepidermoid carcinoma (MEC) and 10 adenoid cystic carcinoma (ADC) cases. All 12 MECs (100%) were IMP3 positive, while 30% of ADCs and only 25% of PAs were positive for IMP3. There was a statistically significant relationship between salivary gland tumors and IMP3 immunostaining (P =0.03). As regards to DOG1 results, 12.5% of PAs showed variable luminal positive immunostaining and 40% of ADCs showed weak luminal and abluminal immunostaining while 16.7% of MEC showed cytoplasmic staining. On the other hand, all ADCs (100%) showed moderate p63 reactivity in the nuclei of abluminal cells. All MEC cases (100%) were also p63-positive, showing a strong diffuse nuclear reactivity. A statistically significant relationship was noticed between salivary gland tumors and p63 immunostaining (P <0.05). Conclusion: IMP3 is more sensitive for diagnosis of MEC than ADC. p63 is statistically significant in diagnosing salivary gland tumors (MEC and ADC). On the other hand, DOG1 staining is not sensitive in diagnosis of studied malignant salivary gland tumors, limiting its diagnostic utility.