The broadest definition of molecular pathology is the study of molecules in a disease state. In this context, the molecules studied are DNA, RNA and/or protein. Portions of DNA (known as genes) act as templates for the production of RNA which in turn acts as a template for the production of protein. Molecular pathology tests may look for the presence or absence of protein or RNA, or for an increase or decrease in the amount of these molecules. Other molecular pathology tests look for rearrangements of large portions of DNA (these rearrangments are known as translocations) or for specific changes to the composition of genes (these changes are known as mutations).
Molecular pathology can be used to diagnose disease and/or to guide the prevention and treatment of disease.
As an example of the former, infections by certain viruses (e.g. cytomegalovirus and Epstein-Barr virus) can be diagnosed by molecular testing for the presence of their specific RNAs in blood. In the field of cancer pathology, the demonstration of a specific gene mutation or rearrangement can help confirm the diagnosis of certain lymphomas and sarcomas.
Molecular pathology can help with the prevention and/or treatment of disease in several ways. First, tests that look for inherited genetic disease allow for preventative measures to be given to the tested patients and/or their relatives; as an example of this, colorectal cancer patients can be tested for the presence of inherited mutations in genes such as APC. Second, molecular tests can help monitor the response of certain diseases to treatment and can detect whether or not the disease has returned, e.g. Bcr-Abl testing in leukaemias. Finally, there has been great recent interest in using molecular testing to predict the response of certain ‘solid’ cancers to specific drugs. This predictive testing forms the basis of ‘personalised medicine’ for such cancer patients, and includes: HER2 testing in breast and gastric cancer; EGFR and ALK1 testing in lung cancer; BRAF testing in melanoma; and KRAS testing in colorectal cancer. This form of predictive testing is currently a particular growth area in molecular pathology, and therefore represents the initial primary focus of the ACP Molecular Pathology Committee.
Molecular Pathology Committee
Professor Mohammad Ilyas (Chair, Pathological Society of GB & Ireland representative)
Dr Newton Wong (Vice Chair)
Dr F Amary
Dr Rachel Butler (Association of Clinical Genetic Science representative)
Dr David Gonzalez-de-Castro
Professor Manuel Salto-Tellez
Dr Philippe Taniere (UK NEQAS Molecular Genetics representative)
Dr Richard Byers
Dr Emily Shaw
Dr Harry Haynes
Members of Council who also attend this committee
Dr I Chaudhry (Chair of the ACP Histopathology Committee)
Dr I Frayling