Hereditary nonpolyposis colorectal cancer (HNPCC) is comprised of the following: the cancer family syndrome (CFS), or Lynch syndrome II, which shows early-onset proximal colonic cancer predominance and other associated extracolonic adenocarcinomas, particularly endometrial carcinoma; and hereditary site-specific colon cancer (HSSCC), or Lynch syndrome I, which shows all of the same characteristics, except for extracolonic cancer. Nine families with CFS and two with HSSCC provided the resource that was tested for biomarkers (see companion article). All families were meticulously evaluated for genealogy and cancer verification. Biologic specimens were obtained during field visits to areas of closest geographic proximity to the families. Cancer education and recommendations for surveillance/management were provided to patients and their physicians. Additionally, 40 families (about 3000 individuals) with either CFS or HSSCC have been ascertained. Syndrome cancers were restricted to direct-line relatives as opposed to nonbloodline relatives, arguing against involvement of environmental factors. One documented clinical feature was a predilection for proximal versus distal colonic cancer in both CFS and HSSCC kindreds. This has important clinical significance in that it clarifies the need for instituting effective surveillance earlier to detect the predominantly proximal colonic cancers.

Nine families with the cancer family syndrome (CFS), or Lynch syndrome 11, and two with hereditary site-specific colonic cancer (HSSCC), or Lynch syndrome I, were investigated for the following potential biomarkers of genotype status: (1) in ritro tetraploidy of dermal fibroblast monolayer cultures; (2) tritiated thymidine uptake ('HdThd) labeling of colonic mucosa; (3) cytogenetics of peripheral blood mononuclear leukocytes; (4) quantitative serum immunoglobulin determinations; (5) methionine dependence in dermal fibroblasts in tissue culture; (6) segregation analysis; and (7) the study of gene linkage with respect to 25 landmark serum and blood group markers. Positive lod scores of 3.19 for linkage of the J k (Kidd blood group) with CFS were obtained. Both in vitro tetraploidy and 'HdThd uptake in the distal colonic mucosal crypt compartments were positively associated with cancer risk status in CFS and HSSCC kindreds. There was a high incidence of polymorphisms of centromeric heterochromatin, including complete inversion. These findings are of particular clinical and genetic significance because HNPCC lacks premonitory signs of cancer risk. If confirmed, they could conceivably enable definition of genotype as early as birth in members of HNPCC kindreds, thereby epabling psychologic preparation and intensive cancer education for improved compliance in surveillance/management programs. These studies also provide new clues about the chromosome(s) bearing the presumed cancer gene(s). For example, CFS gene(s) may possibly be located on chromosome 2, where J k is located. These biomarkers merit intensive study in additional HNPCC kindreds for a more complete assessment of their sensitivity and specificity. Additionally, essential aspects of previous reports involving biologic samples from these and/or similar subject kindreds are included to permit a comprehensive presentation of the combined findings of this consortium to date.Cuncer 56:939-951, 1985.

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