Bcl2 and Human Papilloma Virus 16 as Predictors of Outcome following Concurrent Chemoradiation for Advanced Oropharyngeal Cancer

Abstract

Purpose: Oropharyngeal squamous cell carcinoma (OPSCC) associated with human papilloma virus (HPV) is rapidly growing in incidence. Despite better prognosis than OPSCC associated with traditional risk factors, treatment failure still occurs in a significant proportion of patients. We had identified the antiapoptotic protein Bcl2 as a marker for poor outcome in advanced OPSCC treated with concurrent chemoradiation. To determine whether Bcl2 and HPV together might further characterize treatment response, we examined whether the prognostic value of Bcl2 was independent of HPV status.Experimental Design: Pretreatment tumor biopsies from 68 OPSCC patients were tested for HPV by in situ hybridization and were immunostained for Bcl2 to evaluate relations with disease-free (DFS) and overall survival following platin-based concurrent chemoradiation. Median follow-up among surviving patients was 47 months (range, 10-131 months).Results: Bcl2 and HPV independently predicted DFS and overall survival. Hazard ratios (with 95% confidence interval) for positive versus negative status in bivariate Cox proportional hazard analysis of DFS were 6.1 (1.8-21) for Bcl2 and 0.11 (0.035-0.37) for HPV. Only 1 of 32 HPV-positive/Bcl2-negative tumors recurred. Pretreatment Bcl2 expression was specifically associated with distant metastasis; five of six distant metastases occurred in the <40% of patients whose primary tumors were Bcl2 positive.Conclusions: Independent of HPV status, pretreatment Bcl2 expression identifies a subset of OPSCC patients having increased risk of treatment failure, particularly through distant metastasis, after concurrent chemoradiation. Considering HPV and Bcl2 together should help in devising better personalized treatments for OPSCC. Clin Cancer Res; 16(7); 2138-46. ©2010 AACR.Patients with human papillomavirus (HPV)-related tumors represent an increasing fraction of newly diagnosed squamous cell carcinomas of the head and neck (HNSCC; refs. 1, 2). These tumors, almost solely oropharyngeal squamous cell carcinomas (OPSCC), typically present at an advanced stage by traditional tumor-node-metastasis (TNM) criteria, yet respond better to treatment than do tumors associated with traditional risk factors (3-11). Nevertheless, a significant fraction of HPV-related tumors resist current standards of care, so it is important to find additional ways to determine prognosis and guide therapy.Cellular mechanisms inhibiting apoptosis can contribute to poor treatment outcome. In HNSCC cell lines, we found that high expression of the antiapoptotic protein Bcl2 enhanced tumor-cell survival, in particular after treatment with cisplatin (12, 13). We extended these findings to advanced OPSCC treated with platinum-based concurrent chemoradiation, a current standard of care (9,14,15), and determined that high pretreatment tumor expression of Bcl2 predicted worse clinical outcome (13).These findings suggest that considering HPV and Bcl2 together might further classify OPSCC with respect to therapeutic response. To evaluate th...

North-American survey on HPV-DNA and p16 testing for head and neck squamous cell carcinoma

“…Other centres choose to test for p16 alone, followed by further direct HPV testing if p16 results are unclear or negative [30][31][32]. Research groups have also looked into other molecular markers that may act as further prognostic and/or treatment factors, such as Bcl2 [33]. Recently, RNA in situ hybridization has been shown to be an excellent test for HPV with a sensitivity of 97% and specificity of 93% [34].…”

The Epidemic of Human Papillomavirus and Oropharyngeal Cancer in a Canadian Population

“…Immunohistochemical expression of p16 in oropharyngeal samples is highly correlated with hpv status 14,15 and is used in many centres throughout Canada because it is inexpensive and easily implemented in any pathology lab. Although most opcs are clearly positive or negative by p16 immunohistochemistry, ambiguous staining patterns are not infrequent 15 .…”

“…Other methods include conventional pcr, which appears to yield a high rate of false positives 15 , in situ hybridization, and real-time pcr. The authors have had experience with in situ hybridization and have previously demonstrated a very high correlation with p16 status 14 ; however, other investigators have reported difficulties optimizing the assay and a poorer correlation with p16 and E6/ E7 expression 15 . We currently favour real-time pcr, with all samples tested in triplicate and repeated if any discrepancies arise.…”

Histopathologic risk factors in oral and oropharyngeal squamous cell carcinoma variants: An update with special reference to HPV-related carcinomas

“…A small minority of HPV+ OP SCC show atypical clinical behavior following treatment including poor OS, DSS and Disease free survival (DFS) (12,26,27). Some cases may be associated with multicentric disease in the mucosa of the upper aerodigestive tract excluding the oral cavity.…”

“…However, certain relevant molecular profiles have been proposed. These include over-expression of Bcl2, EGFR, and BclxL, (27,30,31). EGFR is a transmembrane tyrosine kinase, its function affects cell cycle progression, apoptosis, angiogenesis, tumor cell mobility and metastasis.…”