Scientists have uncovered evidence that cancers have been spreading for centuries among shellfish, particularly cockles. This discovery, published in the peer-reviewed journal Nature, has the potential to reshape the way cancer is perceived and treated.
Researchers from the UK’s Wellcome Sanger Institute and the Universidade de Santiago de Compostela in Spain, in collaboration with experts from various countries, utilized DNA sequencing to examine the historical transmission of certain cancers among cockles. Cockles, belonging to one of the oldest groups of animals on Earth, have been found to host contagious cancers known as bivalve transmissible neoplasia (BTN).
Similar to how cancers spread in Tasmanian devils and dogs, BTN is transmitted among cockles through seawater, carrying living cancer cells that multiply and replicate within the host, akin to leukemia, before spreading to infect others.
The international research team collected around 7,000 cockles from 36 locations across 11 countries, including Spain, Portugal, the UK, Ireland, and Morocco. Their findings unveiled the existence of two independent transmissible cancers, hinting at the possibility of more diverse types yet to be discovered.
Dr. Alicia Bruzos, co-first author of the study, remarked, “Having a wider view of the different types of transmissible cancers can give us more insight into the conditions necessary for tumours to evolve and survive long-term.”
Remarkably, these cockle tumours displayed high genetic instability, containing varying numbers of chromosomes—an unusual characteristic for cancers. Dr. Daniel Garcia-Souto, co-first author, noted that the cells in these tumours underwent extreme chromosomal changes and continuous genetic reorganization over hundreds or thousands of years, challenging the notion that cancers require stable genomes to survive long-term.
This unique feature suggests that these transmissible cancers in cockles differ from other known animal cancers, as they do not necessitate a stable genome for survival. Understanding how these cancerous cells tolerate genetic instability could provide valuable insights for developing innovative approaches to treating human cancers.
In an unexpected twist, the researchers identified instances where cockles were co-infected by cells from both types of cancers simultaneously, further deepening the complexity of these transmissible cancers.
Dr. Adrian Baez-Ortega, joint senior author, emphasized that unraveling the origins and evolution of cockle transmissible cancers and understanding their interaction with marine environments could aid in protecting animal populations. Simultaneously, this research offers valuable insights into the survival mechanisms of cancers as marine parasites for thousands of years.
Source: New York Post