A literature review on oral basaloid squamous cell carcinomas, with special emphasis on etiology

In the recent years, basaloid squamous cell carcinomas (BSCCs) have gained attention because of (1) observation of a relative increase in the number of tumors arising particularly in head and neck sites, (2) identification of human papillomavirus (HPV) in BSCCs arising predominantly in the oropharynx, and (3) controversies that exist regarding the biological aggressiveness of the tumor. The objective of the present review was to address the issues mentioned above by focusing primarily on oral BSCCs, using literature that has been published in the English language up to 2013. According to the literature review, oral BSCCs were found to be relatively more common in elderly patients with a mean age of 64 years. A male predominance with a male/female ratio of 3:1 was observed. The predominant site was the tongue, with almost half of the reported cases occurring at this site, followed by the floor of the mouth and palate. With reference to habit history, majority were found to be tobacco and alcohol users. However, only 3 studies revealed data on HPV status of purely oral BSCC, and according to the results of these studies, of the 17 tumors tested, 4 had harbored high-risk HPV. Furthermore, most oral BSCCs were in an advanced clinical stage, namely, stage III or IV with T3 or T4 lesions and cervical lymph node metastasis at initial presentation, whereas 41% of patients had presented with local recurrences and 45% had died of the disease. In conclusion, although, the present literature review found enough evidence to consider tobacco and alcohol as risk factors for the development of oral BSCC, steps should be taken to fill the gap in our knowledge that exist with reference to contribution of oncoviruses, particularly HPV in the etiology of oral BSCC.