Overall aim of the Concerted Action was: to further our understanding of the somatic and hereditary bases of human epithelial cancer using follicular and C-cell (medullary) tumours of the thyroid as a model.
- To extend the scope of molecular analyses by greatly increasing the pool of thyroid tumour and blood samples available to European laboratories.
- To maximise the efficiency of use of such samples by promoting exchange of expertise, reagents and data.
- To support specific collaborative projects within this area.
Research is currently focused on the fundamental role of abnormalities in oncogenes and anti-oncogenes in thyroid cancer. The availability of large sample numbers deoxyribonucleic acid has permitted the reliable exclusion of 2 candidate oncogenes, erbB and erbB2, an important negative result in view of their involvement in many other tumour types. It has also facilitated more reliable estimates of the frequency of 2 abnormalities which are rare in thyroid cancer as a whole, (ie mutation of the p53 gene and rearrangement of the ret gene) and promises to identify subtypes of thyoid tumour in which they occur more frequently. The most common somatic genetic abnormality in thyroid cancer, mutation of the ras family of genes, has been confirmed, and furthermore the exchange of samples between European laboratories has played a key role in resolving a particularly important discrepancy concerning the stage in tumorigenesis at which it occurs. This increase in knowledge of the somatic events in thyroid cancer will facilitate the clinical application of oncogene research to diagnosis and prognosis. In the hereditary thyroid cancer syndromes, cross evaluation between laboratories has helped to standardise and improve the precision of the main biochemical test for early detection of carriers of the cancer gene(s). Accurate early diagnosis has been further helped by the improvement in the predictive value of genetic tests, again made possible by the availability of larger numbers for deoxyribonucleic acid (DNA) probe evaluation. These improvements are translating directly into fewer deaths from thyroid cancer.
As a research tool, thyroid tumours have a significance out of proportion to their relatively low incidence. Tumours of the thyroid follicular cell represent an ideal experimental model for analysing the step-wise accumulation of somatic mutations that underlies tumour development and progression. Tumours of the thyroid C-cell are an excellent example of an autosomal dominant inherited tumour syndrome. The major limitation in the study of thyroid tumours, however, is their rarity. The purpose of this Concerted Action is to facilitate such research by increasing the pool of tumour and serum samples available for analysis, firstly by increasing the number of collection centers and secondly by optimising efficient use of the collected samples through a programme of collaborative research.