CD34-positive dendritic interstitial cells may be associated with the regulation of tumor growth. This association has been studied in various human neoplasms, especially skin tumors. In this study, we evaluated the distribution of dendritic interstitial cells and myofibroblastic cells at the tumor periphery of various benign and malignant salivary gland neoplasms.
Forty-nine cases of salivary gland tumors were selected: 16 pleomorphic adenomas, 12 Warthin tumors, 8 polymorphous low-grade tumors, 5 adenoid cystic carcinomas, 6 acinic cell carcinomas, and 2 mucoepidermoid carcinomas. Immunohistochemical analysis was performed by using antibodies for CD34 (dendritic cells) and alpha-smooth muscle actin (myofibroblast) on formalin-fixed, paraffin-embedded archival tissue. Staining intensity was graded as marked (3+), moderate (2+), weak (1+), and absent (0).
Staining intensity for CD34 was 3+ in 24 (86%) of 28 benign tumors (pleomorphic adenomas and Warthin tumors) and 6 (29%) of 21 malignant tumors (polymorphous low-grade tumors, acinic cell carcinomas, adenoid cystic carcinomas, and mucoepidermoid carcinomas) and 2+ in 4 (19%) of 21 malignant tumors. None of the benign tumors displayed 2+ staining with CD34. Three (11%) of 28 benign and 11 (52%) of 21 of malignant tumors failed to stain with CD34. alpha-Smooth muscle actin staining was 3+ in 10 (36%) of 28 benign tumors and 6 (29%) of 21 malignant tumors, and 2+ in 11 (39%) of 28 benign and 2 (9%) of 21 malignant tumors. Five (18%) of 28 benign and 11 (52%) of 21 malignant tumors failed to stain with alpha-smooth muscle actin.
We conclude that the dendritic interstitial cells and myofibroblastic cells may be associated with the regulation of tumor growth in salivary gland tumors.