CD276 is an immune checkpoint antigen. Elevated CD276 expression is a hallmark of many malignancies and is frequently associated with poor prognosis. Elevated CD276 levels have been reported in bladder cancer (BC)1; however, CD276 sex disparities have not yet been investigated in detail. Male patients suffer more frequently from BC.2 Elevated CD276 expression correlates with androgen receptor expression in prostate cancer.3 Sex disparities have been reported in other malignancies.4,5 Thus, in this exploratory study, we investigated CD276 expression in pathology-defined tumor areas in 98 BC samples from 80 male and 18 female patients using a tissue microarray. In another study, BC tumor samples from 6 male and 4 female patients were examined for CD276 expression using immunohistochemistry and morphometry. In our first study, samples from male patients scored significantly higher (191.6 ± 71.18; n = 80; p = 0.037) than those from females (152.4 ± 61.85; n = 18; Fig. 1A). In the second study, the areas of CD276 expressing cells were significantly larger in BC samples from males than in tissue samples from female patients with BC (p < 0.001, n = 10; Fig. 1B). We previously reported that elevated CD276 levels did not differ significantly in patients with T stages T2a–T4x.1 The current study complements these findings and adds the following preliminary results: differences in CD276 expression as a function of pathological grading (i.e., G2, G2–3, G3), lymph node status (N0, N+), invasion of tumor cells in lymph vessels (i.e., V0, V1), previous therapy (bacillus Calmette-Guerin instillation, surgery), and absence of secondary malignancies (not shown). The results of this exploratory study suggest that the expression of CD276 is significantly elevated in the BC tissues of male patients. This elevated expression of CD276 may contribute to the higher incidence and different clinical course of BC in male patients and may influence the outcome of CD276-dependent anti-immune checkpoint therapies. In contrast, CD276-dependent therapies may be less effective in females. However, this aspect should be explored in detail in future studies.Figure 1.: Expression of CD276 in BC tissue evaluated using a TMA and immunohistochemistry. (A) BC tumor TMAs were generated from samples from 18 female and 80 male patients, and the expression of CD276 was detected using antibody staining and scored using microscopy. Significantly higher CD276 expression was recorded in BC samples from male patients (TMA score, 191.6; p < 0.037) than in those from female patients (TMA score, 152.4). The x-axis depicts sex, and the y-axis depicts the TMA score (for technical details, see the study Aicher et al. 1 ). (B) Areas of CD276 staining cells were recorded in BC tissue samples from 4 female and 6 male patients, as indicated by the x-axis. In samples from male patients, significantly larger areas of CD276+ cells were observed than in samples from female patients (p < 0.001; 126 tissue samples from 10 patients). The y-axis represents the area of CD276+ cells per field of view in arbitrary units. BC = bladder cancer; TMA = tissue microarray.Acknowledgments We thank T. Abruzzese, C. Bock, V. Kramer-Potapenia, M.Sc., and M. Kühs for their excellent technical assistance, and Chaim Goziga for expert help in the preparation of the artwork. Statement of ethics This study was approved by the Joint Ethics Committee of the University of Tuebingen and University of Tuebingen Hospital under file numbers 341/2002 and 804/2020/B02, respectively. The study was conducted in compliance with the WMA Declaration of Helsinki on the ethical principles for medical research and in accordance with all relevant guidelines and regulations. Conflicts of interest statement AS is an Editor-in-Chief of Current Urology and confirms no involvement in any stage of this article’s review process, ensuring unbiased editorial decision-making. The remaining authors have no conflicts of interest to disclose. Funding source This project was supported in part by grants from the Deutsche Forschungsgemeinschaft DFG (GRK2543 # 429049495), European Commission (EURO-Stars # E! 115301/ 01QE2133C), Leuze-Stiftung (# D30.34666), and institutional funds. Author contributions SW, LER, JH, WKA, BA: Laboratory experiments, experimental data generation, data evaluation, manuscript draft preparation, and artwork; NH, BA, JH, SW: Provision and preparation of clinical tissue samples; VB: Expert pathological evaluation; AS, WKA: Funding, study design, project management, and supervision; All authors: Revisions of the manuscript and artwork. Data availability Data and materials will be disclosed to colleagues in academia upon written, justified, and comprehensible requests from the corresponding author.
Harland et al. (Mon,) studied this question.