Characterization of CD8+ and FOXP3+ T-Cell Ratios in Tumor and Stromal Compartments of Penile Squamous Cell Carcinoma: An Analysis Across Histologic Subtypes and Grades

BackgroundThe balance between CD8+ cytotoxic T cells and FOXP3+ regulatory T cells within the tumor microenvironment is crucial in cancer progression. This study aimed to characterize CD8+/FOXP3+ T-cell ratios in tumor and stromal compartments of penile squamous cell carcinoma (SCC) across different histologic subtypes and grades.MethodsThis retrospective study analyzed 1 tissue microarray block (144 spots from 35 patients). CD8 and FOXP3 immunohistochemistry was performed. Ratios of CD8+/FOXP3+ T cells per high-power field were categorized as CD8 > FOXP3 or CD8 ≤ FOXP3 in tumor and stromal compartments. Associations with histologic subtype (including WHO classification) and grade were examined.ResultsSeventy-nine spots (55%), representing 23 unique patients, were evaluable. Median intratumoral CD8+ and FOXP3+ counts were 5 and 4 per high-power field, respectively. Stromal median counts were 22 (CD8+) and 38 (FOXP3+) per high-power field. No statistically significant associations were found between CD8+/FOXP3+ ratios and histologic grade in either tumor (<i>P</i> = .529) or stromal compartments (<i>P</i> = .660). Similarly, no significant associations were observed with histologic subtype, though a non-significant trend (<i>P</i> = .09) was noted between stromal ratio and subtype.ConclusionsThis study characterized CD8+ and FOXP3+ T-cell infiltrates and their ratios in penile SCC, revealing distinct patterns between tumor and stromal compartments. In this cohort, significant associations with histologic grade or subtype were not observed. These findings underscore the need for larger, prospective studies incorporating HPV status and clinical outcomes to elucidate the role of these immune ratios.