Abstract The aim of this study was to identify
tumor parenchyma
cells exhibiting immunohistochemical profile of
stem cells by evaluating the immunoreactivity of OCT4 and CD44 in a number of cases of
salivary gland neoplasms. The sample consisted of 20
pleomorphic adenomas, 20
mucoepidermoid carcinomas, and 20
adenoid cystic carcinomas located in major and
minor salivary glands. The expression of OCT4 and CD44 was evaluated by the percentage of positive
cells and the intensity of expression. All studied cases showed positive expression of OCT4 and CD44 and higher values than the
control groups. For OCT4,
luminal and non-
luminal cells were immunostained in the case of
pleomorphic adenomas and
adenoid cystic carcinomas. Moreover, the immunoreactivity of CD44 was particularly evident in the non-
luminal cells of these lesions. In
mucoepidermoid carcinomas, there was immunoreactivity for both markers in squamous and intermediate
cells and absence of
staining in mucous
cells. For both markers, a significantly higher immunostaining was verified in
neoplasms located in the major
salivary glands compared with lesions in
minor salivary glands (p<0.001). In the total sample and in
minor salivary glands,
malignant neoplasms exhibited higher immunoreactivity for OCT4 than
pleomorphic adenoma. A significant moderate positive correlation (r = 0.444 and p ≤ 0.001) was found between OCT4 and CD44 immunoexpression in the total sample. The high expression of OCT4 and CD44 may indicate that these
proteins play an important
role in identifying
tumor stem cells.