Stromal CD8+ lymphocytic infiltration constitutes an independent prognostic marker for better overall survival in patients with oropharyngeal squamous cell carcinoma (OSCC). However, scoring of (novel) biomarkers is often complicated by the lack of standardised methodology which hampers their use in daily clinical practice. We therefore performed a comparative analysis to evaluate the importance of choice of materials and methods in CD8 assessment in patients with OSCC. Other immune cell markers, that is, CD3 and FoxP3 were taken into account as well.
Immunohistochemical analysis of CD3, CD8 and FoxP3 was performed on whole-tissue sections from 101 treatment-naive patients with OSCC. A comparison of different immune cell markers was made for biopsy material versus resection material when available. Also, different scoring strategies, that is, quantitative versus semi-quantitative analysis were compared with each other.
Comparison of biopsy material versus resection material proved a good agreement for expression of the CD3+ T cells (κ = 0.712, ρ = 0.853), CD8+ T cells (κ = 0.659, ρ = 0.764) and FoxP3+ T cells (κ = 0.783, ρ = 0.802). The comparison of quantitative versus semi-quantitative assessment demonstrated strong correlations for the CD3+ T cells (ρbiopt = 0.617, ρresection = 0.634), CD8+ T cells (ρbiopt = 0.656, ρresection = 0.675) and FoxP3+ T cells (ρbiopt = 0.537, ρresection = 0.720).
Immunohistochemical analysis of CD3, CD8 and FoxP3 can be performed adequately on biopsy as this appears to be representative for the whole tumour. In addition, this can be done adequately in a semi-quantitative manner without the use of more expensive and time consuming machinery.
Clinical trial identification
Legal entity responsible for the study
Prof. Sylvie Rottey
agency for Innovation by Science and Technology (IWT)
All authors have declared no conflicts of interest.