Researchers at The University of Texas MD Anderson Cancer Center have identified a previously overlooked reason why non-melanoma skin cancers become particularly aggressive in people with weakened immune systems. Rather than lacking the immune cells normally found inside tumors, these patients appear to retain many of the same cell types—but the cells no longer communicate effectively. The finding, published August 5, 2026, in Cell, could reshape how scientists understand and treat skin cancer in organ-transplant recipients and patients with certain blood cancers.
Non-melanoma skin cancer is already the most frequently diagnosed cancer in the United States. Its most common forms include basal cell carcinoma and squamous cell carcinoma, with squamous cell tumors posing a greater risk of invasion and spread. In people receiving immunosuppressive drugs after organ transplantation, or in those whose immune systems are compromised by hematologic malignancies, these cancers occur more often and can behave far more aggressively. Tumors that might otherwise be controlled can grow rapidly, recur after treatment, or become fatal.
The clinical challenge is intensified by the limited availability of immunotherapy. Immune checkpoint inhibitors, which restore the ability of T cells to attack cancer, have transformed treatment for many advanced skin cancers. However, stimulating the immune system in an organ-transplant recipient can trigger rejection of the transplanted organ. As a result, physicians must balance cancer control against the risk of severe immune complications, leaving some immunosuppressed patients with few systemic treatment options.
The MD Anderson-led team analyzed tumor samples from 138 people with non-melanoma skin cancer, comparing individuals with weakened immune systems with patients whose immune function was considered normal. The clinical differences were substantial. Patients in the immunosuppressed group experienced shorter disease-free survival, and their five-year overall survival was 33%, compared with 68.8% among immunocompetent patients. These outcomes suggested that immunosuppression was influencing more than the initial development of cancer; it was also changing the biology of the tumor environment.
Scientists have traditionally suspected that immunosuppressed tumors might be missing the immune cells needed to recognize and destroy malignant tissue. Using single-cell analysis, however, the researchers found that many of the same immune-cell populations were present in both groups. Single-cell technologies examine gene activity and other molecular features in individual cells rather than averaging signals across an entire tumor. This approach allowed the investigators to distinguish not only which cells were present, but also how those cells were functioning and communicating.
The key defect appeared to involve macrophages, immune cells that engulf cellular debris, release signaling molecules, and help organize responses against infection and cancer. Macrophages can influence whether T cells become activated, where they move within a tumor, and how strongly they respond to abnormal cells. In the tumors from immunosuppressed patients, macrophages were present but showed impaired communication with neighboring immune cells. Their molecular signals were less effective at directing an antitumor response, creating an immune environment in which cancer could progress despite the presence of immune defenses.
The analysis also revealed reduced receptor diversity in the immune cells associated with immunosuppressed tumors. Receptors are molecular sensors that allow cells to detect antigens, inflammatory signals, and other indicators of cellular stress or danger. A narrower receptor repertoire may limit the range of cancer-related features that immune cells can recognize. In practical terms, the immune system may contain the necessary cellular components but lack the flexibility and coordination required to identify and respond to the tumor efficiently.
Moran Amit, M.D., Ph.D., assistant professor of Head and Neck Surgery at MD Anderson, said the findings challenge the long-standing assumption that these patients simply have fewer important immune cells. The study’s co-leaders also included Kunal Rai, Ph.D., Frederico Gleber-Netto, D.D.S., Ph.D., Priyadharsini Nagarajan, M.D., Ph.D., and Michael Migden, M.D. Together with collaborators, they concluded that immune-cell quality and interaction may be as important as immune-cell quantity when determining whether a tumor remains controlled.
The discovery points toward treatment strategies designed not only to activate T cells, but also to repair the tumor’s innate immune network. Future approaches could seek to restore macrophage function, broaden receptor diversity, strengthen communication between macrophages and lymphocytes, or enhance innate immune signaling without provoking the dangerous systemic activation associated with conventional immunotherapy. The researchers are now investigating whether these dysfunctional cells can be stimulated or returned to a more effective state. Because the cells are already present, therapies might be able to rehabilitate the local immune response rather than build it from scratch.
The work was supported by the National Institutes of Health, including the National Cancer Institute and the National Institute of Craniofacial Research, the Cancer Prevention and Research Institute of Texas, and institutional funding from UT MD Anderson. The researchers say that defining the precise molecular defects in macrophages and their signaling networks will be essential before new therapies can be tested. For patients whose cancers are difficult to treat because their immune systems cannot safely be activated, understanding how immune communication fails could provide a new route toward effective and more precisely targeted care.
Subject of Research: Non-melanoma skin cancer and immune dysfunction in immunosuppressed patients
News Publication Date: August 5, 2026
Web References: The University of Texas MD Anderson Cancer Center, https://www.mdanderson.org/ ; Cell study, https://www.cell.com/cell/fulltext/S0092-8674(26)00863-9
References: Cell
Image Credits: The University of Texas MD Anderson Cancer Center
Keywords: Skin cancer, non-melanoma skin cancer, squamous cell carcinoma, immunosuppression, macrophages, immune cells, cancer immunology, immunotherapy, tumor microenvironment, cancer research, oncology
Tags: aggressive skin cancer in immunocompromised individualsdysfunctional immune cell communicationimmune cell dysfunction in tumor microenvironmentimmune checkpoint inhibitors in compromised immune systemsimmunosuppressed skin cancerimpact of immune cell signaling on tumor aggressivenessnon-melanoma skin cancer in transplant patientsnovel insights into immunerole of immune communication failure in skin cancer progressionskin cancer risk in hematologic malignanciestreatment challenges for immunosuppressed skin cancerstumor immune microenvironment in skin cancer
