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J F Lynch

Publications and source records attributed to J F Lynch.

At least 37 records · Page 2Linked to original sources
PubMed1997

Cancer genetics in the new era of molecular biology.

The role of primary genetic factors in the etiology of cancer has become of intense interest to the research and clinical community. This interest has been heightened by recent discoveries that germ-line mutations such as BRCA1 and BRCA2 in hereditary breast cancer are responsible for an increasing percentage of common solid tumors. A potpourri of proto-oncogenes and tumor-suppressor genes has been identified in hereditary as well as certain common sporadic and rare cancer types, and new cancer genes will likely be discovered every month to account for the 5 to 10% of the cases of cancer that can be attributed to primary genetic factors. Molecular mechanisms in the pathogenesis of hereditary cancer can result in more-targeted cancer-control measures. At least four mutator genes (MHS2, MLH1, PMS1 and PMS2) appear to account for 70-80% of hereditary nonpolypoid colorectal cancer (HNPCC). When one of these germ-line mutations is present in an HNPCC family, the physician is then able to determine the patient's lifetime cancer destiny with an accuracy of about 90% (limited only by the penetrance of the gene). This will enable highly targeted surveillance to be initiated early, such as colonoscopy beginning at ages 20 to 25 or prophylactic subtotal colectomy. Also, in multiple endocrine neoplasia syndromes (MEN 2A and 2B), the identification of the culprit RET proto-oncogene now enables a secure diagnosis and permits testing of children who might benefit from prophylactic total thyroidectomy. Central to translation of these momentous molecular genetic discoveries into patient care is the necessity of determining who requires DNA testing. The cancer family history is the linchpin in making this decision.

Adaptor Proteins, Signal Transducing↗
PubMed1997

A descriptive study of BRCA1 testing and reactions to disclosure of test results.

BACKGROUND: The identification of the BRCA1 gene is a powerful tool for predicting a patient's lifetime risk for carcinoma of the breast and ovary when she has hereditary breast/ovarian carcinoma (HBOC) syndrome. The process of BRCA1 testing and genetic counseling and participants' reactions to test results, are described. METHODS: Education about the natural history of HBOC syndrome and the pros and cons of genetic testing was provided to 14 HBOC families comprised of 2549 bloodline relatives. Of these, 388 underwent DNA testing. After informed consent was given by participants, formal linkage analysis and gene mutation studies were performed on the families. Qualitative data on intentions and emotional reactions were collected by physicians/counselors during the genetic counseling sessions. RESULTS: Of those tested, 181 received their results after further genetic counseling. Seventy-eight of them were positive and 100 were negative for BRCA1 gene mutation. Three had ambiguous findings. The most common reasons given for seeking DNA testing were concern about risk to children and concern about surveillance and prevention. Prophylactic mastectomy was considered by 35% of women who tested positive, whereas prophylactic oophorectomy was considered an important option by 76%. Twenty-five percent of both BRCA1 positive and negative individuals were concerned about discrimination by insurance companies. Eighty percent of those who tested negative reported emotional relief, whereas over one-third of those who tested positive reported sadness, anger, or guilt. CONCLUSIONS: DNA testing of patients with HBOC syndrome must be performed in the context of genetic counseling. The authors' results demonstrate the many complex clinical and nonclinical issues that are important in this process.

Adult↗
PubMed1997

Etiology, natural history, management and molecular genetics of hereditary nonpolyposis colorectal cancer (Lynch syndromes): genetic counseling implications.

We estimate that 5-10% of virtually all forms of cancer are due to a primary hereditary etiology. However, a hereditary cancer diagnosis is often missed because the family history of cancer is given short shrift in medical practice. Hereditary nonpolyposis colorectal cancer (HNPCC) certainly fits this estimate, although some studies suggest that a minimum of 2% with a range as high as 10% of the total colorectal cancer burden is due to HNPCC. Mutations in one of the four mismatch repair genes, i.e., hMSH2, hMLH1, hPMS1, and hPMS2, account for about 70% of HNPCC kindreds. Other germ-line mutations are likely to be identified to account for the remainder of HNPCC patients. By far the most common HNPCC mutations involve hMSH2 and hMLH1, with hPMS1 and hPMS2 accounting for only about 3% of such families. Prior to these molecular genetic discoveries, the genetic counselor could only provide the patient with an estimate of a 50% likelihood of manifesting HNPCC based on the counselee having one or more first-degree relatives manifesting syndrome cancers in their direct genetic lineage. Because DNA testing has become available in families with known mutations, we have provided pretest group education in the form of a family information service with intensive education about the natural history, genetic risk, surveillance, and options for management of HNPCC, as well as discussion of the potential for fear, anxiety, apprehension, and insurance or employer discrimination that might impact on this DNA testing. Following informed consent, these relatives were then counseled on a one-to-one basis. Using DNA-based genetic counseling involving hMSH2 or hMLH1, we have provided this service to four extended HNPCC kindreds. Details of this genetic counseling experience on these four kindreds will be discussed.

Adaptor Proteins, Signal Transducing↗
PubMed1996

Overview of natural history, pathology, molecular genetics and management of HNPCC (Lynch Syndrome).

Hereditary non-polyposis colorectal cancer (HNPCC) predisposes to cancers of the colon, endometrium and several other extra-colonic sites in the absence of premonitory physical stigmata (Muir-Torre syndrome excepted). Discovery of the several DNA mismatch repair genes (hMSH2, hMLH1, hPMS1, hPMS2) holds the potential for determining the cancer destiny of patients, theoretically in utero. Pre-symptomatic DNA testing is now possible in patients from HNPCC families and will be clinically available once inexpensive and simple tests for these germ-line mutations have been effected. Genetic counseling will be mandatory, given the myriad socio-psychological, insurance, and potentially other personal issues which may impact this knowledge. New findings in the pathology of HNPCC, particularly an increased frequency of interval cancers and the likely accelerated rate of the adenoma to cancer sequence, indicate the need for more frequent colonoscopic surveillance with an option for prophylactic subtotal colectomy in germ-line-positive individuals.

Colorectal Neoplasms, Hereditary Nonpolyposis↗
PubMed1996

Relevance of body weight to apolipoprotein levels in Australian children.

OBJECTIVES: To assess weight and apolipoprotein profiles in a representative sample of primary school children. PARTICIPANTS AND SETTING: 1543 children (936 girls and 607 boys) aged 6-11 years from schools in the Eastern Sydney Area Health Service region in 1994. METHODS: We measured body mass index (BMI) and capillary blood apolipoprotein (apo) B and A-I levels (the carrier proteins for low and high density lipoprotein cholesterol, respectively) as well as lipoprotein (Lp) (a). We related BMI levels to those documented in the 1985 Australian Council on Health, Physical Education and Recreation (ACHPER) survey of school children. RESULTS: Compared with the ACHPER distribution, BMI was increased in the boys but not in the girls; 16.8% of boys were above the 90th percentile of the ACHPER distribution (P = 0.003) and only 6.5% were below the 10th percentile (P = 0.046). There were 45 boys (7.4%) and 53 girls (5.7%) with BMIs above the 95th percentile who were, by definition, obese. They had highly significant increases in apo B (P = 0.003) and apo B: apo A-I ratio (P = 0.0001) compared with children in the normal BMI range (10th-90th percentiles); and 20% of the population, including the obese group, also had Lp(a) levels greater than 300 mg/L. The results in children aged 10 and 11 years were not different from those of the whole group, consistent with an absence of possible confounding effects due to early puberty or smoking. CONCLUSIONS: There was an increase in weight relative to height in boys aged 6-11 years in eastern Sydney, compared with the 1985 ACHPER survey. In both boys and girls with the highest BMI category, levels of apo B and the apo B: apo A-I ratio were significantly increased. As these apolipoprotein changes are correlated closely with early onset atherogenesis and are correctable, their identification offers prospects for prevention.

Apolipoproteins↗
PubMed1996

Familial pancreatic cancer: a review.

The cause of pancreatic cancer remains elusive. The most consistently identified epidemiological risk factor is cigarette smoking. Genetic factors are known to play a significant role in perhaps 5% of the total pancreatic cancer burden. Recent discoveries in molecular biology, particularly germline mutations in inherited conditions which feature pancreatic cancer as an integral part of the tumor spectrum such as in adenomatosis polyposis and hereditary nonpolyposis colorectal cancer, provide powerful incentive to search for other "cancer genes" in this heterogeneous disease. Early detection of this dreadful disease is crucial because its mortality rate approximates its incidence; the ability to identify high-risk patients on the basis of genetic analysis would significantly enhance the potential for early diagnosis. This review addresses the genetic epidemiology of pancreatic cancer and updates our views on screening, surgery, chemotherapy, and genetic counseling, all of which must be used to gain value from genetic predictability of risk status.

Adenomatous Polyposis Coli↗
PubMed1994

Phenotypic variation in hereditary breast cancer. Cancer control implications.

OBJECTIVE: To study hereditary breast cancer pedigrees as models for the elucidation of the natural history of the disease, including early onset; bilaterality; and tumor associations in the heterogeneous variants to aid in its diagnosis and in targeting surveillance and treatment strategies. SETTING: Oncology clinic and hereditary cancer institute. PATIENTS AND OTHER PARTICIPANTS: Physician- or self-referral probands. INTERVENTIONS: None. MAIN OUTCOME MEASURE: Greater understanding of the diagnosis, surveillance, and treatment of hereditary breast cancer. RESULTS: Eighteen pedigrees displayed the phenotypic variation of breast cancer's natural history, obligate gene carriers, and patterns of tumor combinations consonant with genetic heterogeneity. CONCLUSION: Hereditary breast cancer is an important public health problem accounting for about 9% of breast cancer cases. The recent identification of a molecular basis for the identification of a subset of hereditary breast cancer, and thereby the likelihood of the sequencing and cloning of the susceptibility gene(s), will enable targeting of surveillance and treatment measures toward patients at an inordinately high risk of developing cancer. Central to this entire process will be the identification of families with hereditary breast cancer.

Adrenal Cortex Neoplasms↗
PubMed1994

Identification of an HNPCC family.

Hereditary nonpolyposis colorectal cancer (HNPCC) families are frequently missed in the clinical practice setting. The events leading to the diagnosis of a new HNPCC family are described, with particular attention to the importance of a detailed and extended pedigree, and the delivery of pertinent educational and cancer control recommendations to family members. Clinical clues suggestive of HNPCC include young age at colon cancer onset (< 45 yr), proximal colon cancers, multiple colon cancer, and a family history of colonic cancer or certain extracolonic cancers, including endometrium, stomach, small bowel, and urinary tract. Once the diagnosis is established, management of high-risk patients must be based on an awareness of these cardinal features. The recent identification of the cancer susceptibility locus at chromosome 2p15-16 for a subset of HNPCC families and its cloning should lead to a blood test for the carrier state. HNPCC families must nevertheless be identified before high risk family members can enjoy the benefits of progress in molecular biology. This HNPCC family report illustrates some of the important clues necessary for recognizing such families, and the logistics of detailed evaluation.

Adult↗
PubMed1993

DNA screening for breast/ovarian cancer susceptibility based on linked markers. A family study.

BACKGROUND: Linkage to chromosome 17q has been identified in hereditary breast cancer and hereditary breast/ovarian cancer syndrome. A hereditary breast/ovarian cancer syndrome kindred was identified that yielded a highly significant lod score (4.20) when 17q markers were studied, enabling us to identify those who probably carried the cancer-associated gene among the high-risk members of the family. METHODS: High-risk members of the hereditary breast/ovarian cancer syndrome kindred were offered counselling on the basis of 17q markers. Family members responding positively received one-to-one genetic counseling in a structured setting. Subjects were educated before disclosure, and the immediate impact of this information was assessed after disclosure. RESULTS: We provided genetic counseling on the basis of linkage findings to 32 relatives (four men and 28 women). Women who were told they were linkage positive expressed an increased motivation for surveillance and prophylactic surgery. Most women who were told they were linkage negative indicated that they would not proceed with prophylactic surgery but would continue careful surveillance. To date, there has been no evidence of serious emotional disturbances resulting from this disclosure. We believe that this experience can be used by cancer geneticists and physicians in developing protocols for genetic counseling in cancer-associated hereditary disorders. CONCLUSIONS: Physicians must understand current developments in cancer genetics and linkage so that they can be applied to genetic counseling and treatment of high-risk patients.

Adult↗
PubMed1993

Upper gastrointestinal manifestations in families with hereditary flat adenoma syndrome.

BACKGROUND: The hereditary flat adenoma syndrome (HFAS) is characterized by an autosomal dominantly inherited predisposition to multiple colonic adenomas (usually less than 100) with proximal predominance and flat as opposed to polypoid growth. Patients with the syndrome experience colorectal cancers in excess, and the lesions are distributed randomly in the colon. The polyps occur at a later age (median, 55 years) compared with age at onset of polyps in patients with familial adenomatous polyposis (FAP) and patients with the Lynch syndromes. FAP and HFAS are linked to the same locus on chromosome 5q21-q22. METHODS: Upper endoscopic examination was performed on 22 relatives from four families with HFAS. RESULTS: Fifteen patients from three of these families had multiple fundic gland polyps; four had duodenal or gastric adenomas. Periampullary carcinoma was present in two members from separate families. CONCLUSIONS: The authors conclude that the upper gastrointestinal tract pathologic characteristics of HFAS are similar to those described in FAP. Thus, those at risk for HFAS require upper endoscopic screening in addition to meticulous attention to the colon.

Adenocarcinoma↗
PubMed1993

Hereditary ovarian cancer. Heterogeneity in age at onset.

BACKGROUND: Hereditary ovarian cancer (HOC) is heterogeneous, with at least three distinctive syndromes, namely, hereditary site-specific ovarian cancer, hereditary breast-ovarian cancer (HBOC) syndrome, and Lynch syndrome II. Ovarian cancer, in accord with virtually all varieties of adult onset cancer, displays an increasing incidence with advancing age; however, it shows an earlier age of onset in hereditary settings. METHODS: Detailed medical and pathology studies were performed on extended ovarian cancer-prone pedigrees, with special attention given to age at ovarian cancer onset. RESULTS: The age of onset of ovarian cancer is heterogeneous, wherein the average age of onset in HBOC is 52 years, in hereditary site-specific ovarian cancer it is 49 years, and in the Lynch syndrome II it is 45 years, in contrast to its occurrence in the general population, at an average age of 59 years. CONCLUSIONS: These differences are important for the initiation of surveillance and management strategies. Age of onset of ovarian cancer differences in these several hereditary subsets are less striking than they are in the case of other integral forms of cancer in the respective syndromes, such as the breast in the HBOC syndrome. In addition, the phenomenon of extremely early age of onset of ovarian cancer occurs infrequently in HOC when compared to other forms of cancer, such as the breast in HBOC or the colon in Lynch syndrome II. Knowledge about age of onset heterogeneity in HOC may harbor important clues about etiology, pathogenesis, and cancer control.

Adult↗
PubMed1993

Cancer control problems in the Lynch syndromes.

The Lynch syndromes account for about 4 to 6 percent of the total colorectal cancer (CRC) burden. Despite more than two decades of documentation in the literature, many physicians fail to recognize the clinical features of these syndromes. The lack of premonitory physical stigmata, coupled with the absence of a biomarker of cancer susceptibility, mandates full reliance on a well-orchestrated family history for diagnosis. These deficiencies impede cancer control. Even if the diagnosis is made, proper surveillance and management measures that are responsive to the Lynch syndromes' natural history may fail to be implemented. We describe CRC occurrences in patients from four extended Lynch syndrome kindreds. Failures in cancer control were attributable to poor patient compliance and/or to limited physician knowledge about the natural history and surveillance recommendations for the Lynch syndromes. Physicians need to more effectively educate their high-risk patients about the significance of genetic risk, the natural history of CRC, and the appropriate surveillance strategies in the Lynch syndromes.

Adolescent↗
PubMed1993

Genetics, natural history, tumor spectrum, and pathology of hereditary nonpolyposis colorectal cancer: an updated review.

Hereditary nonpolyposis colorectal cancer (HNPCC) dates to Warthin's description of family G, which he began studying in 1895. Warthin's observations were not fully appreciated until 1966 when two families with an autosomal dominant inheritance pattern of nonpolyposis colorectal cancer (CRC) and endometrial cancer were described. This condition was first termed the "cancer family syndrome" and was later renamed HNPCC. Some have proposed that HNPCC consists of at least two syndromes: Lynch syndrome I, with hereditary predisposition for CRC having early (approximately 44 years) age of onset, a proclivity (70%) for the proximal colon, and an excess of synchronous and metachronous colonic cancers and Lynch syndrome II, featuring a similar colonic phenotype accompanied by a high risk for carcinoma of the endometrium. Transitional cell carcinoma of the ureter and renal pelvis and carcinomas of the stomach, small bowel, ovary, and pancreas also afflict some families. Current estimates indicate that HNPCC may account for as much as 6% of the total CRC burden. There are no known premonitory phenotypic signs or biomarkers of cancer susceptibility in the Lynch syndromes. This report will summarize current knowledge, with emphasis on the manner in which this knowledge can be employed effectively for diagnosis and management of HNPCC.

Colorectal Neoplasms, Hereditary Nonpolyposis↗
PubMed1993

Chromosome instability and the FAMMM syndrome.

Our study involved two extended familial atypical multiple mole melanoma (FAMMM) kindreds wherein a sufficient number of informative, high genetic risk, and affected patients enabled collection of pertinent tissue samples (normal skin/fibroblasts and atypical nevi/melanocytes) for cytogenetic analysis, and peripheral blood lymphocytes for DNA usage for linkage studies. We observed marked chromosome instability, as evidence by increased frequencies of cells with chromosomal rearrangements (translocations, deletions, and inversions) in cell cultures from atypical nevi and normal skin. There was no evidence of linkage of the FAMMM disease locus to any of the markers for the short arm of chromosome 1p in these two families. Well-characterized FAMMM kindreds provide an opportunity for biomarker investigations for elucidating heterogeneity and, ultimately, improving cancer control.

Adolescent↗
PubMed1993

The Lynch syndromes.

The Lynch syndromes, also referred to as hereditary nonpolyposis colorectal cancer, are reviewed, with particular attention given to their natural history, diagnosis, surveillance, and management. Lynch syndrome I is characterized by an autosomal dominantly inherited predisposition to early onset colorectal cancer, with proximal predominance and an excess of synchronous and metachronous colorectal cancers. Lynch syndrome II manifests all of the features of Lynch syndrome I but, in addition, shows an integral association with extracolonic cancers, particularly carcinomas of the endometrium and the ovary. There are no premonitory physical signs or biomarkers of genotypic risk. Therefore, the natural history features of the Lynch syndromes are crucial to their surveillance and management.

Adenocarcinoma↗