In the county of Stockholm, between 1970 and 2002, we have previously reported a 3-fold parallel increase in the incidence of tonsillar squamous cell carcinoma (SCC) and the proportion of human papillomavirus (HPV) positive tonsillar SCC. Here, we have followed the above parameters in all patients (n 5 120) diagnosed with tonsillar SCC during [2003][2004][2005][2006][2007] in the same area, and also in correlation to our previous data. Ninety-eight pretreatment biopsies were available and presence of HPV DNA and HPV-16 E6 and E7 RNA were tested by polymerase chain reaction (

Smoking and alcohol are well‐known etiological factors in tonsillar cancer. However, as in cervical cancer, human papillomavirus (HPV) is currently found in a sizable proportion of tonsillar cancer. Recent reports from the U.S. and Finland show an increase in the incidence of tonsillar cancer, without a parallel rise in smoking and alcohol consumption. This study investigates whether the incidence of tonsillar cancer has also changed in Sweden and whether a possible explanation of the increase is a higher proportion of HPV‐positive tonsillar cancer. The incidence of tonsillar cancer between 1970 and 2002 in the Stockholm area was obtained from the Swedish Cancer Registry. In parallel, 203 pretreatment paraffin‐embedded tonsillar cancer biopsies taken during 1970–2002 from patients in the Stockholm area were tested for presence of HPV DNA by PCR. The incidence of tonsillar cancer increased 2.8‐fold (2.6 in men and 3.5 in women) from 1970 to 2002. During the same period, a significant increase in the proportion of HPV‐positive tonsillar cancer cases was observed, as it increased 2.9‐fold (p < 0.001). The distribution of HPV‐positive cases was 7/30 (23.3%) in the 1970s, 12/42 (29%) in the 1980s, 48/84 (57%) in the 1990s and 32/47 (68%) during 2000–2002. We have demonstrated a highly significant and parallel increase both in the incidence of tonsillar cancer and the proportion of HPV‐positive tumors. Hence, HPV may play an important role for the increased incidence of tonsillar cancer. This should definitely influence future preventive strategies as well as treatment for this type of cancer. © 2006 Wiley‐Liss, Inc.

BackgroundHuman papillomavirus (HPV) is a causative factor for tonsillar squamous cell carcinoma (TSCC) and patients with HPV positive (HPV+) TSCC have a better clinical outcome than those with HPV negative (HPV−) TSCC. However, since not all patients with HPV+TSCC respond to treatment, additional biomarkers are needed together with HPV status to better predict response to therapy and to individualize treatment. For this purpose, we examined whether the number of tumor infiltrating cytotoxic and regulatory T-cells in TSCC correlated to HPV status and to clinical outcome.MethodsFormalin fixed paraffin embedded TSCC, previously analysed for HPV DNA, derived from 83 patients, were divided into four groups depending on the HPV status of the tumor and clinical outcome. Tumors were stained by immunohistochemistry and evaluated for the number of infiltrating cytotoxic (CD8+) and regulatory (Foxp3+) T-cells.ResultsA high CD8+ T-cell infiltration was significantly positively correlated to a good clinical outcome in both patients with HPV+ and HPV- TSCC patients. Similarly, a high CD8+/Foxp3+ TIL ratio was correlated to a 3-year disease free survival. Furthermore, HPV+TSCC had in comparison to HPV−TSCC, higher numbers of infiltrating CD8+ and Foxp3+ T-cells.ConclusionsIn conclusion, a positive correlation between a high number of infiltrating CD8+ cells and clinical outcome indicates that CD8+ cells may contribute to a beneficial clinical outcome in TSCC patients, and may potentially serve as a biomarker. Likewise, the CD8+/Foxp3+cell ratio can potentially be used for the same purpose.