RESUMEN
Sarcomatoid renal cell carcinoma (sRCC) is histologically heterogeneous, with variable sarcomatoid amounts intermixed within epithelial carcinoma. However, the current classification for this aggressive disease is homogeneous and agnostic to the sarcomatoid proportion. We investigated whether sRCC subclassification has prognostic value and can reveal the biology underlying dedifferentiation and its clinical aggressiveness. On the basis of the intratumoral abundance of sarcomatoid features, cases were classified as sarcomatoid-high (≥10% sarcomatoid features) or sarcomatoid-low (<10% sarcomatoid features) in a cohort of 104 consecutive patients with sRCC undergoing nephrectomy at a single center. In comparison to sarcomatoid-low patients (n = 52), sarcomatoid-high patients (n = 52) had significantly shorter overall survival (median 14.5 vs 62.9 mo; p < 0.001), which was confirmed on multivariable analysis, and significantly shorter median metastasis-free survival among patients with clinically localized disease (10.7 vs 39.0 mo; p = 0.043). Transcriptomic analyses of 45 sRCC tumors revealed significant upregulation of nine hallmark pathways related to cell cycle/proliferation, epithelial-to-mesenchymal transition, reactive oxidative species, and interferon-α signaling among sarcomatoid-high (n = 24) versus sarcomatoid-low (n = 21) tumors. Categorization into transcriptomic clusters revealed predominance of proliferative, inflammatory, and immune effector phenotypes among sarcomatoid-high tumors, versus a hypoxia/angiogenesis phenotype among sarcomatoid-low tumors. Overall, these findings indicate prognostic value for sRCC subclassification into high versus low sarcomatoid groups and highlight key biology underlying the differences in clinical outcomes. PATIENT SUMMARY: Sarcomatoid renal cell carcinoma (sRCC) is a highly aggressive form of kidney cancer. The percentage of sarcomatoid features varies among tumors, but sRCC is still defined as a single kidney cancer type. Our results show that grouping patients according to their percentage of sarcomatoid features improves prediction of whether their tumors will become metastatic or lethal, and reveal molecular differences that may be important for this disease. Future assignment of sRCC to high and low sarcomatoid groups may help in guiding research and patient management.
RESUMEN
BACKGROUND: Studies evaluating peripheral patient samples show radiation can modulate immune responses, yet the biological changes in human tumors particularly at the cellular level remain largely unknown. Here, we address how radiation treatment shapes the immune compartment and interactions with cancer cells within renal cell carcinoma (RCC) patient tumors. METHODS: To identify how radiation shaped the immune compartment and potential immune interactions with tumor cells we evaluated RCC tumors from patients treated only with nephrectomy or with radiation followed by nephrectomy. Spectral flow cytometry using a 35-marker panel was performed on cell suspensions to evaluate protein expression within immune subsets. To reveal how radiation alters programming of immune populations and interactions with tumor cells, we examined transcriptional changes by single-cell RNA sequencing (scRNAseq). RESULTS: Spectral flow cytometry analysis revealed increased levels of early-activated as well as effector programmed cell death protein-1 (PD-1)+ CD8 T-cell subsets within irradiated tumors. Following quality control, scRNAseq of tumor samples from nephrectomy-only or radiation followed by nephrectomy-treated patients generated an atlas containing 34,626 total cells. Transcriptional analysis revealed increased transition from stem-like T-cell populations to effector T cells in irradiated tumors. Interferon (IFN) pathways, that are central to radiation-induced immunogenicity, were enriched in irradiated lymphoid, myeloid, and cancer cell populations. Focused cancer cell analysis showed enhanced antigen presentation and increased predicted TRAIL-mediated and IFN-mediated interactions between tumor cells and the same effector T-cell subsets increased by radiation. TRAIL and IFN pathways enriched in irradiated tumors were associated with survival in patients treated with immunotherapy. CONCLUSIONS: These findings identify the source of IFN enrichment within irradiated RCC and reveal heightened levels of PD-1+ CD8+ T-cell subsets and increased probability of interactions with tumor cells following standalone radiation treatment. This study provides a window into the irradiated tumor-immune microenvironment of patients and rationale for treatment combinations.
