Cancer researcher who was fascinated by cellular renewal
Professor Christopher Potten, who has died aged 71, was a pioneer in a topic that, 40 years after his first studies, remains central in human biology: the organisation of cellular renewal in the epithelial tissues that line our body surfaces. The surface of the skin and the lining of the gut shed hundreds of millions of cells each day, cells that must be replaced by the multiplication of the stem cells that lie beneath the surface.
Potten was fascinated by this process and its consequences for cancer research. In the early 1970s, following the finding that the epidermis had an ordered structure, he proposed that the skin was organised into "epidermal proliferative units" in which single stem cells lay at the bottom of larger, organised columns of daughter cells, which matured into flattened dead cells as they moved towards the surface and were shed.
This led Potten to the concept of a discrete set of stem cells rather than a homogeneous population of cells of equal potential. With his colleagues at the Paterson Institute for Cancer Research in Manchester, his rigorous work laid the basis for the present concept of the stem cell niche, the environment in which stem cells are found and which regulates stem-cell fate.
Potten next turned his attention to the intestine, where again he was able to demonstrate a discrete population of stem cells. He showed that a few of these were exquisitely sensitive to radiation, preferring to "commit suicide" by a process known as apoptosis, rather than attempting to repair damage to their DNA. This suicide response required the activity of a protein called p53, subsequently dubbed "the guardian of the genome". Potten hypothesised that it was an altruistic response in which the cells died, rather than expose the organism to the cancer risk of incompletely repaired genetic damage. This helped to stimulate research interest in the apoptotic process in the development of new cancer treatments.
Potten was born in Calcutta. His father was in the Indian navy and captained a minesweeper. At the end of the war, the family returned to the UK. Potten studied for his BSc in botany and zoology at Queen Mary, University of London, before moving into radiation biology, with an MSc at Guy's hospital, a PhD at the University of London and a DSc at the University of Manchester.
In 2000, after 30 years as head of the department of epithelial biology at the Paterson Institute, Potten retired and founded a company, Epistem, to continue his research and take it into practical clinical and therapeutic applications. He had the satisfaction in 2002 of using his accumulated knowledge to design and publish a series of experiments to provide strong support for another stimulating but controversial idea, the "immortal strand" hypothesis, on which he had worked with its originator, John Cairns, in the 70s.
This stated that the stem cells renewing a tissue protect the organism against cancer by always partitioning the DNA strand containing the errors that result from copying to the daughter cell that will be shed from the tissue. This work both completed the circle of Potten's earlier ideas, and opened new possibilities for further study.
Potten was awarded a life fellowship from the Cancer Research Campaign (now Cancer Research UK), and the International Marie Curie and Weiss medals for services to radiation research. From 1988 to 2003, he served as chief editor of the journal Cell and Tissue Kinetics, which in 1991 was renamed Cell Proliferation. He was a generous and supportive colleague, whose opinion was often sought. He was always ready to help colleagues with their own research and was especially helpful and encouraging to young people.
Potten married Sarah Chasmar in 1964. Five years after her death in 2002, he married Carol Griffiths. She survives him, as do three sons and two stepdaughters.
• Christopher Stanislaus Potten, biologist, born 30 November 1940; died 3 August 2012