Two-dimensional (2D) monolayer cell culture models are the most common method used to investigate tumor cells in vitro. In the few last decades, a multicellular spheroid model has gained attention due to its adjacency to tumors in vivo. The aim of the present study was to investigate immunohistochemical differences between these two cell culture systems. The FaDu, CAL27 and SCC25 head and neck squamous cell carcinoma (HNSCC) cell lines were seeded out in monolayer and multicellular spheroids. The FaDu and SCC25 cells were treated with increasing doses of cisplatin and irradiation. CAL27 cells were not used in theproliferation experiments, since the spheroids of CAL27 cells were not able to process the reagent in CCK-8 assays. Furthermore, they were stained to present alterations of the following antigens: Ki‑67, vascular endothelial growth factor receptor, epithelial growth factor and survivin. Differences in growth rates and expression patterns were detected in certain HNSCC cell lines. The proliferation rates showed a significant divergence of cells grown in the three‑dimensional model compared with cells grown in the 2D model. Overall, multicellular spheroids are a promising method to reproduce the immunohistochemical aspects and characteristics of tumor cells, and may show different response rates to therapeutic options.

Malnutrition is a frequent comorbidity in head and neck cancer patients and has been shown to impair immunotherapy response in other cancer types. The geriatric nutritional risk index (GNRI) assesses malnutrition using the patient’s ideal weight, actual weight, and serum albumin. The aim of this study was to evaluate the prognostic relevance of malnutrition as determined by the GNRI for the response to immunotherapy in recurrent and/or metastatic head and neck squamous cell carcinoma (R/M HNSCC). A total of 162 patients with R/M HNSCC who received immune checkpoint inhibitors were included. The associations between the GNRI and progression-free survival (PFS), overall survival (OS), and the disease control rate (DCR) were computed. Univariable analysis showed worse PFS for GNRI ≤ 98 (p < 0.001), ECOG performance status (PS) ≥ 2 (p = 0.012), and enteral (p = 0.009) and parenteral (p = 0.015) nutritional supplementation, and worse OS for GNRI < 92 (p < 0.001), ECOG PS ≥ 2 (p < 0.001), and enteral (p = 0.008) and parenteral (p = 0.023) nutritional supplementation. In our multivariable model, GNRI ≤ 98 (p = 0.012) and ECOG PS ≥ 2 (p = 0.025) were independent prognostic factors for PFS. For OS, GNRI < 92 (p < 0.001) and ECOG PS ≥ 2 (p < 0.001) were independent prognostic factors. A GNRI ≤ 98 was significantly associated with a lower DCR compared to a GNRI > 98 (p = 0.001). In conclusion, our findings suggest that the GNRI may be an effective predictor for response to immunotherapy in R/M HNSCC.