Expression of DOG1 (Using SP31) in Poorly Differentiated Carcinoma of the Head and Neck

BACKGROUND: The calcium-activated chloride channel protein discovered on gastrointestinal stromal tumour 1 (DOG1) is expressed in a variety of normal and neoplastic tissues. DOG1 is a specific marker for gastrointestinal stromal tumour. In the head and neck region, DOG1 is a sensitive discriminator for acinar cell carcinoma. Only a few publications have presented data concerning the expression of DOG1 in head and neck squamous cell carcinoma (HNSCC). The expression of DOG1 in HNSCC appears to be associated with a poor prognosis. The aim of this study was to analyze the expression pattern of DOG1 in poorly differentiated carcinoma of the upper aerodigestive tract.

MATERIALS AND METHODS: A total of 84 specimens from 31 patients with carcinomas of the upper aerodigestive tract were immunohistochemically investigated for DOG1 expression. Inclusion criterion was poorly to undifferentiated carcinoma of the head and neck, but samples of the same resection site that exhibited moderate or well-differentiated squamous cell carcinoma were also enrolled. Immunoreactivity in carcinomas was estimated using a visual score (0: negative; 1: basally positive, 2: parabasally positive, 3: completely positive, 4: basally and parabasally positive).

RESULTS: Fifteen out of 84 specimens were immunoreactive to antibody to DOG1 (17.8%). DOG1 immunoreactivity was restricted to eight patients (25.8%). However, DOG1 expression was considerably heterogeneous in tumours, with three (9.6%) cases showing a positive reaction in all samples. Basal and parabasal staining patterns (five specimens each) dominated.

DISCUSSION: This study demonstrated expression of DOG1 to be restricted to some poorly differentiated carcinomas of the upper aerodigestive tract. Although the proportion of DOG1-positive carcinomas was moderate compared to results of previous studies on head and neck cancer tissues, DOG1 expression possibly indicates a subset of HNSCC. Further studies are necessary to investigate the heterogeneity and clinical relevance of DOG1 expression in HNSCC.