A particular genetic risk for mesothelioma may be behind the few cases where cancer develops just a few years after asbestos exposure. That is the word from researchers at Australia’s Flinders University and the Asbestos Diseases Research Institute.
Latency is the time it takes after exposure to a cancer-causing agent for signs of cancer to show up. Malignant mesothelioma has one of the longest latency periods of any cancer. In most cases, it takes about 40 years for mesothelioma to develop. As a result, mesothelioma is rare in people under 65.
But, in rare cases, mesothelioma develops earlier in life. These cases have sometimes been dismissed as being unrelated to asbestos. But in a new journal article, mesothelioma experts from Australia say asbestos probably does play a role in many of these shorter-latency cases. They say the length of the latency may be related to a person’s genetic mesothelioma risk profile.
Mesothelioma and the Path to Malignancy
Malignant mesothelioma is an extremely rare cancer. Fewer than 3,000 patients receive a mesothelioma diagnosis in the US each year. The numbers are higher in Australia due to the country’s long history of asbestos production and use. But it is still uncommon.
Some types of cancer seem to develop spontaneously in people with inherited risk factors. But even people with a genetic mesothelioma risk do not usually get this cancer. Asbestos is the toxic catalyst that makes the difference.
When a person with underlying genetic mesothelioma risk lives or works around asbestos, the chance of getting the disease is much higher. Asbestos stays in the body for decades. It causes long-term irritation and inflammation at the cellular level. An exposed person may start to develop symptoms 20, 30, or even 50 years after exposure.
It is rare for a person under 65 to get mesothelioma. Scientists used to think that mesothelioma cases in younger people were less likely to be asbestos-related. But the new Australian case study suggests otherwise. It suggests that certain kinds of genetic mesothelioma risk may result in a shorter latency after asbestos exposure.
A Case Study of Genetic Mesothelioma Risk
The new case study features a 40-year-old man who developed peritoneal mesothelioma just 8.5 years after asbestos exposure. The patient had germline mutations in the RAD51 and p53 genes. These mutations raised his genefic mesothelioma risk.
Researchers at Flinders University documented the case in the International Journal of Environmental Research and Public Health. They say the man may be an example of someone whose genetic mesothelioma risk profile increased the chances for shorter mesothelioma latency.
“Emerging data regarding the significance of inherited mutations leading to a predisposition to mesothelioma suggest that the causative effect of asbestos may be associated with shorter latencies in a subset of patients,” writes lead researcher Sonja Klebe. Klebe is an Associate Professor in the Department of Anatomical Pathology at Flinders Medical Centre.
There is also evidence that mesothelioma latency may not really be as long as scientists think. The World Health Organization recently recognized a pre-mesothelioma condition called mesothelioma in situ. Mesothelioma in situ can start five years or more before symptoms show up. Dr. Klebe says this may impact how doctors quantify latency in the future.
Klebe, S, et al, “The Significance of Short Latency in Mesothelioma for Attribution of Causation: Report of a Case with Predisposing Germline Mutations and Review of the Literature”, December 17, 2021, International Journal of Environmental Research and Public Health, https://www.mdpi.com/1660-4601/18/24/13310