Economic and Practical Factors in Diagnosing HNPCC Using Clinical Criteria, Immunohistochemistry and Microsatellite Instability Analysis.
OBJECTIVE
To determine a cost-efficient strategy for HNPCC molecular diagnostic testing.


METHODS
138 families referred to a Regional Genetics Service had hMLH1 and hMSH2 mutation analysis. The sensitivity and specificity of clinical selection criteria with or without immunohistochemistry (IHC) and microsatellite instability (MSI) analysis to further refine case selection and the effect of these approaches on the cost of mutation analysis were examined.


RESULTS
Clearly deleterious mutations were identified in 49/138 (35.5%) of all families tested. The most sensitive criteria for identifying families with MMR mutations were the full Bethesda guidelines but these have poor specificity. IHC and MSI were useful pre-screening tools.


CONCLUSIONS
A cost-efficient approach in laboratories where IHC and/or MSI analysis are available, is to use inclusive (non-specific) criteria to select cases, followed by IHC and then MSI. Where one or both results are abnormal, proceed to further mutation analysis. Where MSI or IHC or tumour blocks are not available, more restrictive clinical criteria may be more appropriate for cost-efficient case selection.
Wessex Clinical Genetics Service, Princess Anne Hospital, Southampton SO16 5YA, UK. de1@soton.ac.uk.
Francesca
F
Pigatto
Adrian
A
Bateman
David
D
Bunyan
Paul
P
Strike
Esta
E
Wilkins
Claire
C
Curtis
Philippa
P
Duncan
Denzil
D
May
Karen
K
Nugent
Diana
D
Eccles