Higher Altitude Linked to More Aggressive Skin Cancer Types in 17-Year Study

People living at higher altitudes may be more likely to develop aggressive forms of skin squamous cell carcinoma, according to a retrospective study of skin cancer cases in Kashgar, Xinjiang, China, published in BMC Cancer.

The research team, led by Rui Zou, Ying Lin, Guiqing Liao and Menglan Xie, reviewed pathological records of skin cancer patients treated between 2008 and 2024, a period spanning 17 years. The researchers sorted and classified the pathological types and differentiation grades of the tumours, collected the recorded five-year survival rates of the patients, and extracted geographical altitude information from each patient’s usual place of residence, which they then analysed in classified groups.

As altitude increased, the probability of skin squamous cell carcinoma presenting as a moderately or poorly differentiated type rose, a relationship the authors report as statistically significant (P < 0.05). In other words, among patients in this region, those from higher-elevation residences were more likely to have tumours classified in the less differentiated categories than patients from lower elevations.

The study also found that survival differed sharply by differentiation grade. The five-year survival rate of patients with moderately and poorly differentiated skin squamous cell carcinoma was significantly lower than that of patients with well-differentiated tumours (P < 0.05).

Quantifying this survival gap, the researchers report that compared with patients who had well-differentiated cutaneous squamous cell carcinoma, patients with moderately to low differentiated tumours had a 2.75-fold higher risk of tumour-associated mortality (hazard ratio 2.75, 95% confidence interval 1.74–4.35, P < 0.0001). The five-year survival curves of the moderately to low differentiated group showed significant differences from those of the well-differentiated group.

Based on these observations, the authors conclude that altitude may affect the cell differentiation types of skin squamous cell carcinoma and ultimately influence patients’ five-year survival. The study was conducted as a retrospective analysis of a single region’s patient records over nearly two decades, and the authors describe the altitude finding as an unexpected discovery that emerged from their data.

Several caveats are worth noting. The findings derive from one geographic setting, Kashgar in Xinjiang, and the analysis is observational, so it identifies associations rather than demonstrating that altitude causes changes in tumour biology. The published record also notes that this early-release version is subject to further edits and will be replaced by the final version of record. The mechanism behind any link between residence altitude and tumour differentiation grade is not established by the data presented.

Nevertheless, the study adds a geographic dimension to how skin squamous cell carcinoma is classified and staged in a high-altitude population, and suggests that differentiation grade, which is already a routine pathological descriptor, carries substantial prognostic weight in this cohort.

Subject of Research: The association between altitude of residence and the pathological differentiation grade and five-year survival of skin squamous cell carcinoma

Article Title: The altitude can influence the pathological classification of skin cancer and further affect the five-year survival rate of patients: an unexpected discovery

Article References: Zou, R., Lin, Y., Liao, G., & Xie, M. (2026). The altitude can influence the pathological classification of skin cancer and further affect the five-year survival rate of patients: an unexpected discovery. BMC Cancer. https://doi.org/10.1186/s12885-026-16928-w

Image Credits: AI Generated

DOI: 10.1186/s12885-026-16928-w

Keywords: skin cancer, squamous cell carcinoma, altitude, tumour differentiation, five-year survival, retrospective study, Kashgar, Xinjiang, pathology, prognosis, BMC Cancer, epidemiology