Von Hippel-Lindau disease (VHL) is an autosomal dominantly inherited syndrome with high penetrance, characterised by tumours in various organs. The Dutch VHL working group presents guidelines for DNA testing and clinical monitoring, to enhance early detection and treatment of VHL patients in the Netherlands. Diagnosis of VHL is justified in patients presenting with a typical VHL tumour with a positive family history, but patients with a VHL tumour and a negative family history may also have VHL. Diagnosis of VHL can be confirmed by molecular genetic analysis of the VHL gene which is informative in virtually all VHL families. In a patient with (suspicion for) VHL there is an indication for genetic counselling. A protocol for clinical monitoring of VHL is presented and is recommended for: carriers of a VHL germline mutation; members of VHL families with an unknown familial mutation; members of VHL families who decline testing of the familial mutation; patients suspected for VHL, but without a detectable VHL gene mutation.

A family history of breast cancer has long been recognised as a significant risk factor for breast cancer. Quantifying that risk has been approached in publications and practically in a number of different ways. Increasingly regional genetics departments are called upon to help clarify guidelines for referral of women with a family history of breast cancer for genetic testing and to clarify breast cancer risk for women seeking early mammographic screening. This paper represents the current consensus guidelines from the UK Cancer Family Study Group and discusses some of the difficulties surrounding genetic risk estimation.

Protocols for activity aiming at early diagnosis and treatment of inherited breast or breast-ovarian cancer have been reported. Available reports on outcome of such programmes are considered here. It is concluded that the ongoing activities should continue with minor modifications. Direct evidence of a survival benefit from breast and ovarian screening is not yet available. On the basis of expert opinion and preliminary results from intervention programmes indicating good detection rates for early breast cancers and 5-year survival concordant with early diagnosis, we propose that women at high risk for inherited breast cancer be offered genetic counselling, education in ‘breast awareness’ and annual mammography and clinical expert examination from around 30 years of age. Mammography every second year may be sufficient from 60 years on. BRCA1 mutation carriers may benefit from more frequent examinations and cancer risk may be reduced by oophorectomy before 40–50 years of age. We strongly advocate that all activities should be organized as multicentre studies subjected to continuous evaluation to measure the effects of the interventions on long-term mortality, to match management options more precisely to individual risks and to prepare the ground for studies on chemoprevention.

Individuals with one first-degree relative with colorectal cancer diagnosed before age 45 years and those with two first-degree relatives with colorectal cancer run a significantly increased risk (relative risk: 4-6) of developing colorectal cancer. Based on calculation of the mortality due to colorectal cancer for the age group 50-70 years (which is higher than the mortality due to breast cancer) surveillance may be justified, e.g. by colonoscopy at 5-year intervals from the age of 45-50. The total number of people in the Netherlands in this high risk group is estimated at 10,000. The authors conclude that prospective studies are needed to assess the cost-effectiveness of such a programme.

At the recent Tuberous Sclerosis Consensus Conference, a subcommittee proposed recommendations to guide the rational use of diagnostic studies in patients with tuberous sclerosis complex. Recommendations were made for diagnostic evaluation at the time of diagnosis, when testing helps both to establish the diagnosis and to identify potential complications. Additional guidelines were proposed for the ongoing surveillance of established patients to detect later complications of tuberous sclerosis complex. In the absence of comprehensive population studies to govern the use of diagnostic studies in individuals with tuberous sclerosis complex, the panel developed guidelines based on the disorder's natural history, concentrating on complications that are common, clinically significant, and more easily managed when found early. Finally, the group made suggestions for the use of diagnostic tests to identify family members who have tuberous sclerosis complex. Although these recommendations should standardize and improve our use of diagnostic studies in individuals with tuberous sclerosis complex, the clinical approach in a given patient must remain flexible enough to meet the needs of individual patients and families.

Almost 10% of breast and ovarian cancer are inherited, and the majority are linked to BRCA1 and BRCA2 germline mutations. Despite the uncertainty in the management of women gene carriers, consensus guidelines were defined to assist practitioners', and patients' decisions about the health care decisions to be made.

Almost 10% of breast and ovarian cancer are inherited, and the majority are linked to BRCA1 and BRCA2 germline mutations. Despite the uncertainty, consensus guidelines were defined to assist practitioners', and patients' decisions about the health care decisions to be made.

Almost 10% of breast and ovarian cancer are inherited, and the majority are linked to BRCA1 and BRCA2 germline mutations. Despite the uncertainty, consensus guidelines were defined to assist practitioners', and patients' decisions about the health care decisions to be made.

Almost 10% of breast and ovarian cancers are familial, and the majority are linked to BRCA1 and BRCA2 germline mutations. Despite uncertainty about the management of female gene carriers, consensus guidelines have been established to assist practitioners and consultees in making health care decisions.

Consensus was recently reached in the Netherlands regarding the clinical management of dysplastic naevi and the definitions in clinical and pathological diagnostics. The term 'dysplastic' is reserved for histological diagnostics; the term preferred for clinical use is 'clinically atypical naevus'. A naevus is defined as clinically atypical if it meets three of the following five criteria: > or = 5 mm in diameter, vaguely bordered, asymmetrically shaped, irregularly pigmented and a red hue (erythema). Presence of clinically atypical naevi is a main risk factor for melanoma. Dysplastic naevus syndrome (DNS) is present if a patient has a melanoma and one or several clinically atypical naevi. The diagnosis of 'familial DNS' (familial atypical multiple mole-melanoma syndrome, abbreviation FAMMM syndrome) is made if at least two close relatives (including the patient) are known with a melanoma with or without atypical naevi, while one or several (other) relatives have atypical naevi. The risk of melanoma in a gene carrier of familial DNS is close to 100%, while multiple melanomas develop in 30% of the gene carriers. No DNA diagnostics is yet possible in most DNS/FAMMM families, because of the involvement of genes yet unknown. Accordingly, at present it is still too early for DNA diagnostics. Currently, therefore, the diagnosis is based only on anamnestic, clinical and histological grounds.

To provide recommendations for cancer surveillance and risk reduction for individuals carrying mutations in the BRCA1 or BRCA2 genes.

To provide recommendations for cancer surveillance and risk reduction for individuals carrying mutations associated with hereditary nonpolyposis colon cancer (HNPCC).

Cytology, cytochemistry, immunophenotyping and cytogenetic analysis have specific roles in the diagnosis and management of various haematological neoplasms. Careful examination of Romanowsky-stained films of blood and bone marrow is fundamental in all haematological diagnosis and, when considered together with clinical and haematological features, indicates which of the more specialized techniques are most likely to be useful. The major role of cytochemistry is in the diagnosis of acute myeloid leukaemia and the myelodysplastic syndromes. The major role of immunophenotyping is in the diagnosis of the chronic lymphoproliferative disorders and of acute leukaemia which is not obviously myeloid. Cytogenetic analysis has a role in confirming the diagnosis of chronic granulocytic leukaemia and gives important supplementary information in the acute leukaemias and the myelodysplastic syndromes.

The primary objective was to determine clinical practice guidelines for the use of tumor marker tests in the prevention, screening, treatment, and surveillance of breast and colorectal cancers. These guidelines are intended for use in the care of patients outside of clinical trials.