To catch a killer: keeping cancer on the run
Professor Richard Christopherson, Director of the Sydney University Proteome Research Unit, and his team are developing new diagnostic techniques. A breakthrough in protein profiling of cancers that should enable personalised medicine.
2D electrophoresis separates proteins by their isoelectric point then mass-to-charge ratio, enabling Christopherson to identify thousands of proteins in melanoma cells. A process that has uncovered a source of melanoma drug resistance, where higher levels of the proteins Cystatin B, manganese superoxide dismutase and B cell enhancing factor, interfere with cell death, dampening the effects of chemotherapy. “Identifying the source of this resistance is a step towards refining chemotherapy to suit each patient,” explains Christopherson.
Protein profiles can also be generated by DotScan microarrays, a technique developed by Christopherson. A mosaic of microscopic dots of antibodies reacts with a patient’s sample to reveal a profile of marker proteins on the surface of cancer cells.
The extensive surface profiles obtained using DotScan microarrays should enable diagnosis, prognosis and determination of drug sensitivity without additional information. Christopherson is enthusiastic about what this means for cancer patients worldwide. “This technology is a powerful adjunct to current cancer diagnosis. The more we know about the pathology of a cancer, the greater our chance of providing optimum patient care.”
There are 30–40 common types of leukaemia, each with a distinct pattern on DotScan. Samples from 796 people, taken from hospitals in Australia and the US, have been analysed to generate an extensive database of surface protein profiles on leukaemias.
Chronic lymphocytic leukaemia (CLL) is a research focus for Christopherson. DotScan can provide the power to distinguish between indolent and terminal CLL. “At the moment there’s no reliable way to distinguish between the two, which makes advocating aggressive treatment difficult. A version of DotScan developed for CLL will provide a means of matching cancer patients with the appropriate treatment.”
“Each leukaemia is caused by a different combination of up to 90 mutations, so each leukaemia should be treated as an individual disease. DotScan provides a new, systematic method of classification and could potentially identify new types of leukaemia, whilst tailoring chemotherapy to individuals.”
The DotScan technology is covered by international patents and is produced and distributed by the company Medsaic. Focusing initially on two applications, leukaemia and solid tissue tumours, it’s hoped that Medsaic will increase the precision of diagnoses as well as improve medical access to pathology in rural and remote locations.