Lack of CD44 and Sox-2 Overexpression as Two Independent Favourable Prognostic Factors in HPV Positive Patients with Oropharyngeal Cancers.

Introduction: In our earlier publications, in the group of 63 patients with oropharyngeal cancer, we have found HPV16 infection (assessed by qPCR) in 25 tumours (39.7%), immunohistochemical overexpression of CD44, CD98, ALDH1/2 and Nanog in, respectively: 43 (68.2%), 30 (47.6%), 33 (52.4%), and 53 (84.1%) cancers. Analysing CD44, CD98, ALDH1/2, we have also shown that lack of CD44 overexpression indicates excellent prognosis in patients with HPV16 positivity. The aim of the present study was to compare prognostic potential of Nanog, Oct3/4, Sox-2 expression in relation to CD44, CD98, ALDH1/2 immunoreactivity (assessed by us earlier) and clinicopathological features in the subgroups of patients: with HPV16 positivity and HPV16 negativity.

Methods: Status of Oct3/4 and Sox-2 expression was assessed for 63 patients with oropharyngeal cancers based on immunohistochemistry. In survival analysis, two endpoints were applied: overall survival (OS) and disease-free survival (DFS).

Results: Overexpression of Oct3/4 and Sox-2 was found in 0 (0.0%) and 27 (42.9%) of patients. In the subgroup with HPV16 positivity, the DFS for patients with lack of Sox-2 overexpression was significantly (p = 0.003) higher than for patients with Sox-2 overexpression. In the subgroup with HPV16 negativity, Nanog and Sox-2 immunoexpression did not significantly influence OS and DFS. In multivariate analysis performed for the subgroup with HPV16 positivity, lack of CD44 overexpression (p = 0.012) and lack of Sox-2 overexpression (p = 0.027) were positive independent prognostic factors.

Conclusion: Based on CD44 and Sox-2 immunoreactivity, it is possible to differentiate the prognosis of HPV16-positive patients with oropharyngeal cancers.