Diabetes and skin cancers: Risk factors, molecular mechanisms and impact on prognosis

Macrophages, IL-10, and nitric oxide increase, induced by hyperglycemic conditions, impact the development of murine melanoma B16F10-Nex2

Epidemiological studies show a strong correlation between diabetes and the increased risk of developing different cancers, including melanoma. In the present study, we investigated the impact of a streptozotocin (STZ)-induced hyperglycemic environment on B16F10-Nex2 murine melanoma development. Hyperglycemic male C57Bl/6 mice showed increased subcutaneous tumor development, partially inhibited by metformin. Tumors showed increased infiltrating macrophages, and augmented IL-10 and nitric oxide (NO) concentrations. In vivo neutralization of IL-10, NO synthase inhibition, and depletion of macrophages reduced tumor development. STZ-treated TLR4 KO animals showed delayed tumor development; the transfer of hyperglycemic C57Bl/6 macrophages to TLR4 KO reversed this effect. Increased concentrations of IL-10 present in tumor homogenates of hyperglycemic mice induced a higher number of pre-angiogenic structures in vitro, and B16F10-Nex2 cells incubated with different glucose concentrations in vitro produced increased levels of IL-10. In summary, our findings show that a hyperglycemic environment stimulates murine melanoma B16F10-Nex2 primary tumor growth, and this effect is dependent on tumor cell stimulation, increased numbers of macrophages, and augmented IL-10 and NO concentrations. These findings show the involvement of tumor cells and other components of the tumor microenvironment in the development of subcutaneous melanoma under hyperglycemic conditions, defining novel targets for melanoma control in diabetic patients.

Role of Insulin Use and Social Determinants of Health on Non-melanoma Skin Cancer: Results From the Behavioral Risk Factor Surveillance System

BACKGROUND

Non-melanoma skin cancer (NMSC) is a frequent type of malignancy with a steadily increasing incidence rate worldwide. Although NMSC was shown to be associated with diabetes, no studies have addressed the extent to which insulin use influences the risk of NMSC in light of social determinants of health (SDOH). We conducted a quantitative study that examined the interplay between insulin use, SDOH, additional covariates, and NMSC among individuals with diabetes.

METHODS

We based our analysis on the 2020 Behavioral Risk Factor Surveillance System (BRFSS), a national survey conducted yearly in the US. We performed weighted chi-squared test, logistic regression, and survival analyses on 8685 eligible participants with diabetes enrolled in the BRFSS.

RESULTS

Kaplan Meier survival curves showed higher probability of NMSC event-free survival for participants with diabetes using insulin compared to participants with diabetes not using insulin (log-rank test P < .001). Significant associations were detected between insulin use and reduced odds of NMSC (OR .56; 95% CI: .38-.82), and decreased hazard (HR .36; 95% CI: .21-.62), along with indices of SDOH.

CONCLUSIONS

Our findings suggest that socioeconomic differences related to the healthcare system and behavioral patterns are linked to discrepancies in the use of insulin and the development of NMSC.

Clinico-pathological Spectrum of Primary Skin Malignancies in an Indian Tertiary Care Hospital

Background

Skin malignancies are the most common form of malignant disease in the western world, predominantly affecting older age groups. The majority of skin cancers are basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and malignant melanoma, which account for more than 95% of total skin malignancies. However, in India, these constitute only 1-2% of all cancers. There is an increase in incidence in India over 10 years of period. There is scarcity of data on the clinico-pathological profile of these tumours from this geographical region.

Materials and Methods

This was a retrospective study conducted in a tertiary care teaching hospital in which archival records and histopathology sections of all patients of skin carcinomas diagnosed over a period of 5 years (January 2016 to December 2020) were analysed. The clinical parameters and histopathological features of the cases were analysed and correlated for any possible association.

Results

Out of the 230 skin malignancies studied, SCC constituted the most common type (n = 148), followed by BCC (n = 70) and malignant melanoma (n = 12). The tumour commonly presented in the 6th decade of life with slightly higher male preponderance (M: F =1.6:1). Sun-exposed areas were the most common sites, and the common presentations included non-healing ulcer, fungating/cauliflower/polypoidal growth, and hyperpigmented or nodular plaque. In SCC, previous history of diabetes and burns was noted in 10% and 3.4% of the patients, respectively.

Conclusion

SCC is likely the most common histological type of skin malignancies in India. The clinico-pathological profile of skin malignancies of patients depends on multiple factors, notably the skin colour and the geographical location.