Comparative analysis of transforming properties of E6 and E7 from different beta human papillomavirus types.

The cutaneous beta human papillomavirus (beta HPV) types appear to be involved in skin carcinogenesis. However, only a few beta HPVs have been investigated so far. Here, we compared the properties of E6 and E7 oncoproteins from six uncharacterized beta HPVs (14, 22, 23, 24, 36, 49). Only HPV49 E6 and E7 immortalized primary human keratinocytes and efficiently deregulated the p53 and pRb pathways. Furthermore, HPV49 E6, similarly to E6 from the oncogenic HPV16, promoted p53 degradation.

E6 and E7 proteins from different beta-papillomaviruses types do not interfere in UVB-induced apoptosis of HaCaT keratinocytes.

Beta-papillomaviruses (beta-HPV) have been linked to the development of skin cancer in humans. Because both E6 and E7 proteins from beta-HPV have been involved in the potential carcinogenicity of these viruses, we investigated their role on UVB-induced apoptosis in HaCaT cell line. HaCaT cells have been transduced with both E6/E7 using a retroviral system and treated with PRIMA-1. Apoptosis was assessed by flow cytometry to measure mitochondrial membrane potential and DNA fragmentation. HaCat keratinocytes transduced with both E6 and E7 genes of seven beta-HPV types (HPV5, HPV8, HPV14, HPV24, HPV36, HPV38 and HPV49) did not demonstrate any inhibition of UVB-induced apoptosis, even after p53 reactivation through PRIMA-1. Our data suggest that the expression of E6 and E7 exert different modulatory effects on UVB-induced apoptosis according to beta-HPV types and to the cellular genetic context.

Epidemiology of cholangiocarcinoma: an update focusing on risk factors.

Cholangiocarcinoma is relatively rare, but high incidence rates have been reported in Eastern Asia, especially in Thailand. The etiology of this cancer of the bile ducts appears to be mostly due to specific infectious agents. In 2009, infections with the liver flukes, Clonorchis sinensis or Opistorchis viverrini, were both classified as carcinogenic to humans by the International Agency for Research on Cancer for cholangiocarcinoma. In addition, a possible association between chronic infection with hepatitis B and C viruses and cholangiocarcinoma was also noted. The meta-analysis of published literature revealed the summary relative risks of infection with liver fluke (both Opistorchis viverrini and Clonorchis sinensis), hepatitis B virus, and hepatitis C virus to be 4.8 (95% confidence interval [95% CI]: 2.8-8.4), 2.6 (95% CI: 1.5-4.6), and 1.8 (95% CI: 1.4-2.4), respectively - liver fluke infection being the strongest risk factor for cholangiocarcinoma. Countries where human liver fluke infection is endemic include China, Korea, Vietnam, Laos, and Cambodia. The number of infected persons with Clonorchis sinensis in China has been estimated at 12.5 million with considerable variations among different regions. A significant regional variation in Opistorchis viverrini prevalence was also noted in Thailand (average 9.6% or 6 million people). The implementation of a more intensive preventive and therapeutic program for liver fluke infection may reduce incidence rates of cholangiocarcinoma in endemic areas. Recently, advances have been made in the diagnosis and management of cholangiocarcinoma. Although progress on cholangiocarcinoma prevention and treatment has been steady, more studies related to classification and risk factors will be helpful to develop an advanced strategy to cure and prevent cholangiocarcinoma.

The IARC Monographs: Updated Procedures for Modern and Transparent Evidence Synthesis in Cancer Hazard Identification.

The Monographs produced by the International Agency for Research on Cancer (IARC) apply rigorous procedures for the scientific review and evaluation of carcinogenic hazards by independent experts. The Preamble to the IARC Monographs, which outlines these procedures, was updated in 2019, following recommendations of a 2018 expert advisory group. This article presents the key features of the updated Preamble, a major milestone that will enable IARC to take advantage of recent scientific and procedural advances made during the 12 years since the last Preamble amendments. The updated Preamble formalizes important developments already being pioneered in the Monographs program. These developments were taken forward in a clarified and strengthened process for identifying, reviewing, evaluating, and integrating evidence to identify causes of human cancer. The advancements adopted include the strengthening of systematic review methodologies; greater emphasis on mechanistic evidence, based on key characteristics of carcinogens; greater consideration of quality and informativeness in the critical evaluation of epidemiological studies, including their exposure assessment methods; improved harmonization of evaluation criteria for the different evidence streams; and a single-step process of integrating evidence on cancer in humans, cancer in experimental animals, and mechanisms for reaching overall evaluations. In all, the updated Preamble underpins a stronger and more transparent method for the identification of carcinogenic hazards, the essential first step in cancer prevention.