Two of New Zealand's top biomedical researchers have achieved what's considered a "gold medal" in global science -- chalking up 1000 citations of a landmark paper they published 22 years ago.

The 1993 study led by Professor Mike Berridge and research fellow An Tan, both of the Wellington-based Malaghan Institute, is now the most cited original research paper New Zealand has ever produced in the field of cell biology.

It clarified how a common dye-based assay used to measure the proliferation of cells and to screen for anti-cancer drugs worked on a cellular level, challenging the global understanding of clinicians and pharmaceutical companies at that time.

Professor Berridge said that, even though the study was now more than 20 years old, it continued to be cited and referenced by researchers today working in what was the biggest area of biology.


"In the context of understanding cell proliferation, we have become, and I hate to use the term, but world experts in using dye-based assays, which of course are fundamental in the use of virtually every biology and microbiology lab throughout world."

The milestone follows a major paper Professor Berridge had published in leading journal Cell Metabolism last year.

That study demonstrated, for the first time, the movement of mitochondrial DNA between cells in an animal tumour.

After mitochondrial DNA was removed from breast cancers and melanomas in mice, replacement mitochondrial DNA naturally shifted from surrounding normal tissue.

After adopting the new DNA, the cancer cells went on to form tumours that spread to other parts of the body.

It was a leap in the science of cellular biology, and could boost the understanding of human diseases other than cancer, since defective mitochondrial DNA accounts for about 200 diseases and is implicated in many more.

Malaghan Institute director Professor Graham Le Gros said every process or procedure used in modern medicine began somewhere in a lab, and the point of publishing data was to offer findings to the international scientific community to replicate or to critique.

"Over one thousand international peers have used this paper as a foundation to move their own work forward, and while a layperson might scratch their head and ask how understanding which part of a cell -- in this case the part outside the mitochondria -- is the key player in this medical test, it gives clinicians and patients confidence that this test for cancer is fully understood."


Professor Le Gros described Professor Berridge as one of the country's most respected cellular biologists.

"His work continues to push the boundaries of scientific knowledge, as evidenced by his breakthrough with An Tan on mitochondrial DNA trafficking to tumour cells last year.

"We could not be more proud of this achievement -- 1000 citations for work carried out at the Malaghan Institute is another milestone for New Zealand science."