Cancer mortality after kidney transplantation: A multicenter cohort study in Italy

Kidney transplant (KT) recipients are known to be at risk of developing several cancer types; however, cancer mortality in this population is underinvestigated. Our study aimed to assess the risk of cancer death among Italian KT recipients compared to the corresponding general population. A cohort study was conducted among 7373 individuals who underwent KT between 2003 and 2020 in 17 Italian centers. Date and cause of death were retrieved until 31 December 2020. Indirect standardization was used to estimate standardized mortality ratios (SMRs) and corresponding 95% confidence intervals (CIs). Cancer was the most common cause of death among the 7373 KT recipients, constituting 32.4% of all deaths. A 1.8-fold excess mortality (95% CI: 1.59-2.09) was observed for all cancers combined. Lymphomas (SMR = 6.17, 95% CI: 3.81-9.25), kidney cancer (SMR = 5.44, 95% CI: 2.97-8.88) and skin melanoma (SMR = 3.19, 95% CI: 1.03-6.98) showed the highest excess death risks. In addition, SMRs were increased about 1.6 to 3.0 times for cancers of lung, breast, bladder and other hematopoietic and lymphoid tissues. As compared to the general population, relative cancer mortality risk remained significantly elevated in all age groups though it decreased with increasing age. A linear temporal increase in SMR over time was documented for all cancers combined (P < .01). Our study documented significantly higher risks of cancer death in KT recipients than in the corresponding general population. Such results support further investigation into the prevention and early detection of cancer in KT recipients.

Risk of virus and non-virus related malignancies following immunosuppression in a cohort of liver transplant recipients. Italy, 1985-2014

This cohort study assessed, in Italy, the overall pattern of risk of de novo malignancies following liver transplantation (LT). The study group included 2,832 individuals who underwent LT between 1985 and 2014 in nine centers all over Italy. Person-years (PYs) at cancer risk were computed from 30 days after LT to the date of cancer diagnosis, to the date of death or to the end of follow-up. Excess cancer risk, as compared to the general population, was estimated using standardized incidence ratios (SIRs) and 95% confidence intervals (CIs). During 18,642 PYs, 246 LT recipients developed 266 de novo malignancies, corresponding to a 1.8-fold higher cancer risk (95% CI: 1.6-2.0). SIRs were particularly elevated for virus-related malignancies, including Kaposi's sarcoma (SIR = 53.6, 95% CI: 30.0-88.5), non-Hodgkin lymphomas (SIR = 7.1, 95% CI: 4.8-10.1) and cervix uteri (SIR = 5.4, 95% CI: 1.1-15.8). Among virus-unrelated malignancies, elevated risks emerged for head and neck (SIR = 4.4, 95% CI: 3.1-6.2), esophagus (SIR = 6.7, 95% CI: 2.9-13.3) and adrenal gland (SIR = 22.9, 95% CI: 2.8-82.7). Borderline statistically significant elevated risks were found for lung cancer (SIR = 1.4, 95% CI: 1.0-2.1) and skin melanoma (SIR = 2.6, 95% CI: 1.0-5.3). A reduced risk emerged for prostate cancer (SIR = 0.1, 95% CI: 0.0-0.5). These findings underline the need of preventive interventions and early detection of malignancies, specifically tailored to LT recipients.

Sustained activation of detoxification pathways promotes liver carcinogenesis in response to chronic bile acid-mediated damage

Chronic inflammation promotes oncogenic transformation and tumor progression. Many inflammatory agents also generate a toxic microenvironment, implying that adaptive mechanisms must be deployed for cells to survive and undergo transformation in such unfavorable contexts. A paradigmatic case is represented by cancers occurring in pediatric patients with genetic defects of hepatocyte phosphatidylcholine transporters and in the corresponding mouse model (Mdr2-/- mice), in which impaired bile salt emulsification leads to chronic hepatocyte damage and inflammation, eventually resulting in oncogenic transformation. By combining genomics and metabolomics, we found that the transition from inflammation to cancer in Mdr2-/- mice was linked to the sustained transcriptional activation of metabolic detoxification systems and transporters by the Constitutive Androstane Receptor (CAR), a hepatocyte-specific nuclear receptor. Activation of CAR-dependent gene expression programs coincided with reduced content of toxic bile acids in cancer nodules relative to inflamed livers. Treatment of Mdr2-/- mice with a CAR inhibitor blocked cancer progression and caused a partial regression of existing tumors. These results indicate that the acquisition of resistance to endo- or xeno-biotic toxicity is critical for cancers that develop in toxic microenvironments.