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Published on: January 21, 2019
Immunohistochemical distribution of CD9 in parotid gland tumors
Kikuo Sakamoto1, Yasuhiro Nakamura, Tadashi Nakashima
1Department of Otolaryngology, Head and Neck Surgery, Kurume University School of Medicine, Asahi-machi 67, Kurume-shi 830-0011, Japan. skikuo@med.kurume-u.ac.jp
Objective:
CD9 is a member of the tetra-membrane-spanning glycoprotein family called tetraspanin. CD9 suppresses breeding and motion in some types of cancer cells. At present, the expression of CD9 in the salivary gland has not yet been elucidated.
Methods:
We examined the expression of CD9 not only in the normal salivary glands of human embryo and adults but also in the parotid gland tumors using immunohistochemical staining.
Results:
CD9 was not detected in embryos at 18 weeks of gestation, but was observed at 24 weeks in the salivary gland. CD9 was constantly detected in the adult normal parotid gland. In benign parotid gland tumors, CD9 was present in the 11 of 16 pleomorphic adenomas, every Warthin tumors (18/18) and basal cell adenoma (1/1). In contrast, positive staining for CD9 in malignant parotid tumors was observed in only the case of mucoepidermoid carcinomas. Neither acinic cell carcinomas or adenoid cystic carcinomas did show positive reaction in examined cases. The localization of CD9 was also observed in intercalated duct cells.
Conclusion:
There was a statistically significant reduced expression of CD9 in malignant parotid gland tumors as compared to benign parotid gland tumors (P = 0.003).
Insights
CD9 tetraspanin expression is absent in early human embryos but present in adult salivary glands. Malignant parotid tumors show significantly reduced CD9 expression compared to benign tumors.
Area of Science:
- Oncology
- Cell Biology
- Immunohistochemistry
Background:
- CD9 is a tetraspanin protein involved in cell adhesion and motility.
- CD9's role in salivary gland tissue and tumors is not well understood.
- Previous studies suggest CD9 influences cancer cell behavior.
Purpose of the Study:
- To investigate the expression pattern of CD9 in normal human salivary glands.
- To analyze CD9 expression in various benign and malignant parotid gland tumors.
- To determine if CD9 expression differs between benign and malignant parotid tumors.
Main Methods:
- Immunohistochemical staining was used to detect CD9.
- Samples included normal salivary glands from human embryos and adults.
- Parotid gland tumors (benign and malignant) were analyzed.
Main Results:
- CD9 expression was detected in salivary glands from 24 weeks gestation onwards and in adult glands.
- CD9 was present in most benign parotid tumors (pleomorphic adenomas, Warthin tumors, basal cell adenoma).
- Malignant tumors showed limited CD9 expression, notably absent in acinic cell and adenoid cystic carcinomas, but present in mucoepidermoid carcinoma.
Conclusions:
- CD9 expression is developmentally regulated in salivary glands.
- CD9 is frequently expressed in benign parotid tumors.
- A significant decrease in CD9 expression was observed in malignant parotid tumors compared to benign ones.
