[1133] Use of Cytokeratins 10 and 19, p16, and pRb as a Diagnostic Tool for Determining the Primary Site of Cervical Lymph Nodes Metastases of Occult Squamous Cell Carcinoma

CK Jung, JM Park, YJ Choi, KY Lee, DI Sun, MS Kim. College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea

Background: Cervical lymph node metastases from unknown primary sites account for approximately 2% to 9% of all head and neck malignant lesions. Squamous cell carcinoma is the most common type of all cervical metastatic carcinomas. Many investigators have studied the utility of immunologic expression of various protein markers in identification of the primary site of origin of a metastatic carcinoma. However, to date, there is no specific antibody for determining the site of origin of metastatic squamous cell carcinoma.
Design: We collected the 101 consecutive patients with cervical nodal metastasis who had undergone neck dissection for the treatment of known head and neck squamous cell carcinoma. The primary sites included 16 oral cavity, 38 oropharynx, 26 hypopharynx, and 21 larynx. We validated differential expression of nine protein markers, cytokeratins 5/6, 8/18, 10, 13, 14, and 19, p16, p75, and pRb in 101 cases of cervical node metastases, and evaluated the use of this immunohistochemical panel as a potential diagnostic tool for determining the primary site.
Results: Cytokeratin 10 expression was frequently observed in oral cavity primary tumor (62.5%) than in pharynx (14.1%) and larynx primary (33.3%). Cytokeratin 19 staining was less frequently observed in oral cavity primary (37.5%) than in pharynx (71.9%) and larynx (61.9%) primary. Expression of p16 and altered pRb status (0% or >50%) were exclusively observed in oropharynx primary tumors. In contrast, laryngeal primary tumors were negative for p16 in nearly all cases (20 of 21). Cytokerains 5/6, 8/18, 13 and 14, and p75 were noncontributory in differentiating these entities.
Conclusions: In the diagnosis of an unknown primary in patients with metastatic squamous cell carcinoma in cervical lymph nodes, cytokeratins 10 and 19 staining may be used in the diagnosis of oral cavity primary, and expression of p16 and altered pRb status are strongly suggestive of an oropharyngeal primary. The absence of p16 staining may also be helpful in the diagnosis of laryngeal primary.
Category: Head & Neck

Monday, March 9, 2009 1:00 PM

Poster Session II # 170, Monday Afternoon