Molecular diagnosis on tissues and cells: how it affects training and will affect practice in the future

On 25th November 2011, a symposium organized by the Royal College of Pathologists, entitled 'Molecular diagnosis on tissues and cells', took place in London. As trainees in histopathology and cytopathology, we were stimulated to consider the role that molecular biology is likely to play in future practice and how this is addressed by our own training. The symposium provided a basis for this article. Routine samples requiring molecular analysis are equally relevant to histopathologists and cytopathologists, and molecular biology laboratories are now using cytological as well as histological material for diagnostic testing, allowing different specimen types to be used as and when they are most appropriate. The most widely used types of molecular analysis in routine cellular pathology are EGFR testing in lung cancer, molecular testing of thyroid nodules, fluorescence in situ hybridization testing of urine samples, clonality analysis in lymphoma testing, HER2 testing in breast and gastric cancer, KRAS testing in colorectal cancer, intraoperative assessment of breast cancer sentinel nodes, molecular testing of gastrointestinal stromal tumours and mismatch repair protein analysis. Of these, the majority in the UK are carried out on histopathology samples, although many are applicable to cytological samples if adequate material is obtained. We are particularly encouraged by the potential of molecular diagnostic cytology in traditionally difficult areas, such as intraoperative assessment. We believe that increasing reliance on molecular diagnostic techniques will also herald changes in training.