Mutagen sensitivity as a predisposing factor in familial oral cancer

Pedigree analysis of the oral cancer (OC) patients registered at our Centre had disclosed familial aggregation of oral cancer which hitherto has not been largely reported. There is a paucity of information on the genetic determinism for familial oral cancer predisposition. Therefore, we investigated constitutional chromosome abnormalities and bleomycin-induced chromosome sensitivity of 7 familial and 10 sporadic oral cancer patients and 14 unaffected family members (first-degree relatives) to determine whether these factors could give any clues regarding cancer-predisposing factors. Neither the oral cancer patients nor the unaffected family members showed any constitutional chromosomal abnormalities. However, with regard to bleomycin sensitivity, there was significant difference between the oral-cancer patients and unaffected relatives. The mean b/c value was 1.68 ± 0.48 for familial OC patients, 1.12 ± 0.36 for sporadic OC patients and 0.52 ± 0.18 for the unaffected family members (p < 0.001). A noteworthy observation was that one unaffected family member also showed bleomycin hypersensitivity and expressed a mean b/c value of 1.32, at the initiation of the study. That patient later developed oral carcinoma. This clearly demonstrates that mutagen hypersensitivity among unaffected relatives in OC families may be related to cancer predisposition. The mutagen sensitivity study is being continued in a larger series of subjects, for the development of a cytogenetic marker for prediction of cancer susceptibility. © 1996 Wiley-Liss, Inc.     

Serum selenium and vitamin E concentrations in families of lung cancer patients

Whether or not serum selenium and vitamin E (alpha-tocopherol) concentrations were changed was examined among healthy families of lung cancer patients. Family members as a whole (115 sons and daughters of 55 patients with primary lung cancer) were found to have a trend to lower serum selenium levels (0.116 +/- SD 0.024 microgram/ml, 0.05 less than P less than 0.1). Particularly among families of adenocarcinoma patients, the mean level was significantly lower (0.111 +/- 0.019 microgram/ml, P less than 0.05) than that (0.122 +/- 0.014 microgram/ml) in age-ratio matched controls who did not have cancer patients among their second-degree relatives. Serum vitamin E levels (11.85 +/- 2.85 micrograms/ml) were significantly lower among family members of adenocarcinoma patients than the controls (14.1 +/- 3.1 micrograms/ml, P less than 0.01). Serum selenium and vitamin E levels were significantly lower in lung cancer patients (n = 37, mean age, 63.9 +/- 11.2 yr) than in the controls (P less than 0.001). These data suggest that there are familial factors in serum selenium and vitamin E levels among families of lung cancer patients.     

Expression of folate sensitive and aphidicolin induced chromosomal fragile sites in familial neuroblastoma

The expression of folate sensitive and aphidicolin induced fragile sites in the blood lymphocyte chromosomes of affected and unaffected members from 2 neuroblastoma families were studied. The subjects included 4 neuroblastoma patients, and 9 of their clinically healthy first degree relatives and corresponding number of age and sex matched controls. Lymphocytes cultured in folate deprived culture medium showed rare fragile sites at band p13.1 of chromosome 1, in a frequency of 3%-5% in all the 4 neuroblastoma patients. In aphidicolin treated cultures, the patients and unaffected members in neuroblastoma families, showed hypersensitivity to aphidicolin, as evidenced by the significant increase in percentage of aberration/cell (ab/c) and damaged cells (dc), over that of controls (P < 0.01). Aphidicolin induced fragile sites were more pronounced in chromosomes 1 and 2. A larger number of subjects have to be studied to prove whether altered fragile site expression may be a cytogenetic evidence for an individual or familial cancer predisposing genetic constitution.     

Decentralized colonoscopic surveillance with high patient compliance prevents hereditary and familial colorectal cancer

Although colonoscopic surveillance is recommended both for individuals with known hereditary colorectal cancer (HCRC) syndromes and those with a more moderate familial colorectal cancer (FCRC) history, the evidence for the benefits of surveillance is limited and surveillance practices vary. This study evaluates the preventive effect for individuals with a family history of CRC of decentralized colonoscopic surveillance with the guidance of a cancer prevention clinic. We performed a population based prospective study of 261 patients with HCRC or FCRC, recorded in the colonoscopic surveillance registry at the Cancer genetics clinic, University Hospital of Umeå, Sweden. Colonoscopic surveillance was conducted every second (HCRC) or fifth (FCRC) year at local hospitals in Northern Sweden. Main outcome measures were findings of high-risk adenomas (HRA) or CRC, and patient compliance to surveillance. Estimations of the expected numbers of CRC without surveillance were made. During a total of 1256 person years of follow-up, one case of CRC was found. The expected numbers of cancers in the absence of surveillance was between 9.5 and 10.5, resulting in a standardized incidence ratio, observed versus expected cases of CRC, between 0.10 (CI 95 % 0.0012–0.5299) and 0.11 (CI 95 % 0.0014–0.5857). No CRC mortality was reported, but three patients needed surgical intervention. HRA were found in 5.9 % (14/237) of the initial and in 3.4 % (12/356) of the follow-up colonoscopies. Patient compliance to the surveillance program was 90 % as 597 of the planned 662 colonoscopies were performed. The study concludes that colonoscopic surveillance with high patient compliance to the program is effective in preventing CRC when using a decentralized method for colonoscopy surveillance with the guidance of a cancer prevention clinic.     

Definition of candidate low risk APC alleles in a Swedish population

Many families experience an apparently inherited increased risk of colorectal cancer (CRC) similar to the known syndromes familial adenomatous polyposis (FAP) and hereditary nonpolyposis colorectal cancer (HNPCC). Besides these high-risk syndromes, approximately 10% of all CRC cases come from families with 2 affected 1st-degree relatives, and even 1st-degree relatives to a single case of CRC are at increased risk. Risk subjects from these families frequently show polyps at colonoscopy, which suggests the APC gene as a good candidate susceptibility gene for these attenuated polypotic syndromes. We used the sensitive DHPLC technique to search for possible predisposing germline mutations in the entire APC gene in 91 risk subjects from these high- and low-risk syndromes with unknown predisposing genes. Most exons were also screened for mutations in 96 normal controls and 96 colorectal cancer cases. In our study we probably have identified the most common APC variants in a Swedish population. Among 30 germline variants identified, 1 clearly pathogenic nonsense mutation and 11 putative pathogenic variants (10 missense and one 3' UTR) were found in 20 index patients (22%). Twelve silent as well as 5 intronic variants were considered nonpathogenic. Two of the missense variants found here, E1317Q and D1822V, have previously been related to a difference in risk of colorectal cancer. One variant, 8636C>A, located within the 3' UTR region of the APC gene, was suggested to constitute an additional low risk allele with a similar relative risk as the Jewish I1307K mutation (OR = 1.8; 95% CI, 0.96-3.40). The question of whether all the other variants confer an increased colorectal cancer risk warrants future large association studies.     

Genetic testing among high-risk individuals in families with hereditary nonpolyposis colorectal cancer

Hereditary nonpolyposis colorectal cancer (HNPCC) is frequently associated with constitutional mutations in a class of genes involved in DNA mismatch repair. We identified 32 kindreds, with germline mutations in one of three genes hMSH2, hMLH1 or hMSH6. In this study, we purposed to evaluate how many high-risk individuals in each family underwent genetic testing: moreover, we assessed how many mutation-positive unaffected individuals accepted colonoscopic surveillance and the main findings of the recommended follow-up. Families were identified through a population-based registry, or referred from other centres. Members of the families were invited for an education session with two members of the staff. When a kindred was consistent with HNPCC, neoplastic tissues were examined for microsatellite instability (MSI) and immunohistochemical expression of MSH2, MLH1 and MSH6 proteins. Moreover, constitutional mutations were searched by SSCP or direct sequencing of the whole genomic region. Of the 164 subjects assessed by genetic testing, 89 were gene carriers (66 affected - that is, with HNPCC-related cancer diagnosis - and 23 unaffected) and 75 tested negative. Among the 23 unaffected gene carriers, 18 (78.3%) underwent colonoscopy and four declined. On a total of 292 first degree at risk of cancer, 194 (66.4%) did not undergo genetic testing. The main reasons for this were: (a) difficulty to reach family members at risk, (b) lack of collaboration, (c) lack of interest in preventive medicine or 'fatalistic' attitude towards cancer occurrence. The number of colorectal lesions detected at endoscopy in gene carriers was significantly (P<0.01) higher than in controls (noncarriers). We conclude that a large fraction of high-risk individuals in mutation-positive HNPCC families does not undergo genetic testing, despite the benefits of molecular screening and endoscopic surveillance. This clearly indicates that there are still barriers to genetic testing in HNPCC, and that we are unable to provide adequate protection against cancer development in these families.     

Extracolonic features of familial adenomatous polyposis in patients with sporadic colorectal cancer.

We have investigated the occurrence of attenuated extracolonic manifestations (AEMs) of familial adenomatous polyposis (FAP) in patients with non-polyposis colorectal cancer. In a prospective case-control study, we observed that significantly more colorectal cancer patients exhibited AEM than did age and sex-matched controls (19.5% vs 7.5%, P < 0.004). However patients with AEMs do not have occult FAP, as we found no heterozygous adenomatous polyposis coli (APC) gene mutations despite extensive analysis of constitutional DNA. Genome-wide DNA replication errors (RERs) occur in a proportion of colorectal cancers, particularly right-sided lesions and in almost all tumours from hereditary non-polyposis colorectal cancer (HNPCC) patients. As AEMs have been reported in familial colon cancer cases, we investigated the relationship of AEMs to tumour RER phenotype. There was indeed an excess of AEMs in patients with right-sided tumours (30.2% of 53 patients vs 14.7% of 116 patients, P < 0.03) and in those with RER tumours (3 out of 12 patients with RER tumours vs none out of 21 patients with non-RER tumours, P < 0.05). Two patients with AEM were from HNPCC families compared with none of those without AEM (P < 0.05). The association of AEMs with colorectal cancer is intriguing, and we speculate that it may be a manifestation of mutational mosaicism of the APC gene, perhaps associated with a constitutional defect in DNA mismatch pair.     

Diagnosing hereditary colorectal cancer

Although progress in the treatment of patients with colorectal cancer (CRC) has resulted in improved median survival, most patients with metastatic CRC still die of their disease, and essentially all patients with early-stage disease must undergo surgical resection and subsequently face the possibility of adjuvant chemotherapy. As effective screening and prevention strategies for CRC have been developed, identification of individuals with a hereditary predisposition to developing CRC is especially important and provides the opportunity to reduce disease burden in this high-risk population. Increased awareness and improved diagnostic techniques for hereditary CRC syndromes have facilitated more frequent diagnosis and management of a small number of highly penetrant syndromes within families. However, known high-penetrance genetic predisposition syndromes account for a minority of all familial CRC, leaving much of the genetic basis of CRC unexplained. Recent advances in high-throughput genotyping have made possible genome-wide association studies, which have identified novel genetic variants associated with modest increases in CRC risk. While these associations have helped to identify potentially important pathways in CRC carcinogenesis, at the current time, the clinical use of such genetic risk variants in colon cancer risk stratification remains limited.     

Familial relative risk of colorectal cancer: a population-based study

This study aimed to assess the familial relative risk for colorectal cancer (CRC) and its variation according to age and gender. A population-based family study was carried out in France, from 1993 to 1998, including 761 families. Familial CRC risks were estimated from a cohort analysis of the relatives. No obvious decrease in CRC risk was found with increasing age, except when either the proband, or the relative, were in the youngest age class. The effect of the relatives' and probands' ages on the CRC risk differed according to their gender. The cumulative risk of CRC increased at an earlier age in male relatives of probands younger than 60 years of age, than in female relatives. This result suggests that mechanisms specific to females, possibly interacting with genetic factors, explain the difference in the cumulative risks between families with male and female probands.     

Frequency of extra-colonic tumors in hereditary nonpolyposis colorectal cancer (HNPCC) and familial colorectal cancer (FCC) Brazilian families: An analysis by a Brazilian Hereditary Colorectal Cancer Institutional Registry

The two main forms of hereditary colorectal cancer are familial adenomatous polyposis (FAP) and hereditary nonpolyposis colorectal cancer (HNPCC). Some families do not meet all the diagnostic criteria for HNPCC or FAP and are classified as familial colorectal cancer (FCC). Little information is available on the spectrum of tumors related to HNPCC and FCC in South America. Objective: To describe the frequency of malignant tumors in a group of Brazilian families with HNPCC or FCC in an Institutional Hereditary Colorectal Cancer Registry. Material and methods: The study included 61 families (29 HNPCC and 32 FCC) between January 1998 and June 2001. HNPCC families were clinically classified according to the Amsterdam Criteria I or II. FCC families were characterized by the presence of at least two individuals with CRC or extra-colonic tumors associated with the HNPCC spectrum, at least one of them being under 50 years of age. Results: In the 29 families with HNPCC, 201 patients with cancer were identified among 1241 individuals (589 men and 652 women). Among the 201 patients 223 tumors were observed: 137 CRC (55 in men and 82 in women) and 86 extra-colonic (37 in men and 49 in women). In the 32 families with FCC, 146 patients with cancer were identified among 1053 individuals (505 men and 548 women); 158 tumors were observed in 146 patients, 75 CRC (33 in men and 42 in women) and 83 extra-colonic tumors (47 in men and 36 in women). The most frequent extra-colonic primary sites among the HNPCC families were: endometrium (26.5%) and breast (26.5%) (women), and stomach (35.1%) (men). Among the FCC families, the most common primary sites were: breast (27.8%) (women), and stomach (44.4%) (men). Conclusion: The high frequency of endometrial and gastric cancer found was expected, since these tumors are part of the HNPCC spectrum, but the high frequency of breast cancer requires further molecular investigation to determine a possible hereditary predisposition associated with hereditary CRC.     

Familial testicular cancer in a single-centre population

Familial occurrence of testicular cancer suggests a genetic predisposition to the disease. A genetic susceptibility may also be reflected by the occurrence of bilateral testicular neoplasms and the high rates of urogenital developmental anomalies in families prone to testicular cancer. In this study, the proportion of familial testicular cancer cases was analyzed retrospectively in a single-centre population of 693 testicular cancer patients treated between 1977 and 1997 and the relative risk (RR) for first-degree relatives of patients was estimated. In addition, the existence of bilateral testicular neoplasms and urogenital developmental anomalies in familial testicular cancer patients was evaluated. 24 of the 693 patients (3.5%) had a first-degree relative with testicular cancer. These 24 cases belonged to 17 families; in 7 of these 17 families both affected first-degree family members were part of the study population of 693 patients. Consequently, the 693 studied patients belonged to a total of 686 families. Thus, the actual proportion of familial testicular cancer was 2.5% (17 of 686 families). The familial cases consisted of 11 brother pairs, including 2 pairs of identical twins and 1 pair which also had two affected cousins, and 6 father-son pairs (in total 36 cases, 12 treated elsewhere). Estimates of the RR to first-degree relatives showed a 9- to 13-fold increased RR to brothers (P < 0.001) and a 2-fold increased RR to fathers (P = non-significant (n.s)) of testicular cancer patients. Among the 36 patients with familial testicular cancer, 2 (5.6%) had bilateral testicular cancer, 4 (11.1%) had undescended testis, 3 (8.3%) had inguinal hernia, and 1 (2.8%) showed renal hypoplasia. The present data on familial occurrence of testicular cancer may lend support to a role of genetic factors in the aetiology of testicular cancer.     

ATM mutations in patients with hereditary pancreatic cancer

Pancreatic cancers are the fourth most-common cause of cancer-related deaths in the Western world, with >200,000 cases reported in 2010. Although up to 10% of these cases occur in familial patterns, the hereditary basis for predisposition in the vast majority of affected families is unknown. We used next-generation sequencing, including whole-genome and whole-exome analyses, and identified heterozygous, constitutional, ataxia telangiectasia mutated (ATM) gene mutations in 2 kindreds with familial pancreatic cancer. Mutations segregated with disease in both kindreds and tumor analysis demonstrated LOH of the wild-type allele. By using sequence analysis of an additional 166 familial pancreatic cancer probands, we identified 4 additional patients with deleterious mutations in the ATM gene, whereas we identified no deleterious mutations in 190 spouse controls (P = 0.046). When we considered only the mostly severely affected families with 3 or more pancreatic cancer cases, 4 deleterious mutations were found in 87 families (P = 0.009). Our results indicate that inherited ATM mutations play an important role in familial pancreatic cancer predisposition. SIGNIFICANCE: The genes responsible for the majority of cases of familial pancreatic ductal adenocarcinoma are unknown. We here identify ATM as a predisposition gene for pancreatic ductal adenocarcinoma. Our results have important implications for the management of patients in affected families and illustrate the power of genome-wide sequencing to identify the basis of familial cancer syndromes.     

MLH1 and MSH2 constitutinal mutations in colorectal cancer families not meeting the standard criteria for hereditary nonpolyposis colorectal cancer

Genetic diagnosis of hereditary nonpolyposis colorectal cancer (HNPCC) may have a significant impact on the clinical management of patients and their at-risk relatives. At present, clinical criteria represent the simplest and most useful method for the identification of HNPCC families and for the selection of candidates for genetic testing. However, reports of mismatch repair (MMR) gene mutations in families not fulfilling the minimal diagnostic criteria point out the necessity to identify additional clinical parameters suggestive of genetic predisposition to colorectal cancer (CRC) related to MMR defects. We thus investigated a series of 32 Italian putative HNPCC individuals selected on the basis of one of the following criteria: 1) family history of CRC and/or other extracolonic tumors; 2) early-onset CRC; and 3) presence of multiple primary malignancies in the same individual. These patients were investigated for the presence of MLH1 and MSH2 mutations by single-strand conformation polymorphism analysis. Pathogenetic truncating mutations were identified in 4 (12.5%) cases, 3 of them involving MSH2 and 1 MLH1. In addition, 2 missense MLH1 variants of uncertain significance were observed. All pathogenetic mutations were associated with early age (<40 years) at onset and proximal CRC location. Our results support the contention that constitutional MMR mutations can also occur in individuals without the classical HNPCC pattern. Moreover, evaluation of the clinical parameters associated with MMR mutations indicates that early onset combined with CRC location in the proximal colon can be definitely considered suggestive of MMR-related hereditary CRC and should be included among the guidelines for referring patients for genetic testing. Int. J. Cancer 75:835–839, 1998. © 1998 Wiley-Liss, Inc.     

Cancer screening behaviors and risk perceptions among family members of colorectal cancer patients with unexplained mismatch repair deficiency

Communication gaps in families with unexplained mismatch repair (MMR) deficiency (UMMRD) could negatively impact the screening behaviors of relatives of individual with UMMRD. We evaluated cancer risk perception, screening behaviors, and family communication among relatives of colorectal cancer (CRC) patients with UMMRD. Fifty-one family members of 17 probands with UMMRD completed a questionnaire about cancer risk perception, adherence to Lynch syndrome (LS) screening recommendations, and communication with relatives. Clinical data about the probands were obtained from medical records. Thirty-eight participants (78%) were worried from having cancer and twenty-one participants (42%) had undergone colonoscopy in the past 2 years, as recommended for LS families. In terms of screening for extracolonic cancers, only two eligible participants (3.9%) were screened for gastric, endometrial (10.0%), and ovarian (9.5%) cancers. Additionally, 5 participants (10%) underwent genetic counseling. Most participants were not told by anyone to be screened for extracolonic cancers (84, 85, and 95% for gastric, ovarian, and endometrial cancers, respectively). A minority of family members of CRC patients with UMMRD follow cancer screening as recommended for LS families. Health care providers should encourage patients with UMMRD to share information on LS-related cancers screening, especially extracolonic cancers, with their relatives.     

Simultaneous curative resection of double colorectal carcinoma with synchronous bilobar liver metastases

Synchronous colorectal carcinoma (SCRC) indicates more than one primary colorectal carcinoma (CRC) discovered at the time of initial presentation, accounts for 3.1%-3.9% of CRC, and may occur either in the same or in different colorectal segments. The accurate preoperative diagnosis of SCRC is difficult and diagnostic failures may lead to inappropriate treatment and poorer prognosis. SCRC requires colorectal resections tailored to individual patients, based on the number, location, and stage of the tumours, from conventional or extended hemicolectomies to total colectomy or proctocolectomy, when established predisposing conditions exist. The overall perioperative risks of surgery for SCRC seem to be higher than for solitary CRC. Simultaneous colorectal and liver resection represents an appealing surgical strategy in selected patients with CRC and synchronous liver metastases (CRLM), even though the cumulative risks of the two procedures need to be adequately evaluated. Simultaneous resections have the noticeable advantage of avoiding a second laparotomy, give the opportunity of an earlier initiation of adjuvant therapy, and may significantly reduce the hospital costs. Because an increasing number of recent studies have shown good results, with morbidity, perioperative hospitalization, and mortality rates comparable to staged resections, simultaneous procedures can be selectively proposed even in case of complex colorectal resections, including those for SCRC and rectal cancer. However, in patients with multiple bilobar CRLM, major hepatectomies performed simultaneously with colorectal resection have been associated with significant perioperative risks. Conservative or parenchymal-sparing hepatectomies reduce the extent of hepatectomy while preserving oncological radicality, and may represent the best option for selected patients with multiple CRLM involving both liver lobes. Parenchymal-sparing liver resection, instead of major or two-stage hepatectomy for bilobar disease, seemingly reduces the overall operative risk of candidates to simultaneous colorectal and liver resection, and may represent the most appropriate surgical strategy whenever possible, also for patients with advanced SCRC and multiple bilobar liver metastases.     

The potential of the Familial Cancer Registry for anticancer research and medical practice

The Basel Familial Cancer Registry was established in 1982. Detailed pedigree data are obtained from 200 cancer patients every year. Analysis of familial clustering is performed by comparing the tumor spectrum of different family groups defined by the probands' cancer sites and by comparing tumor incidence and spectrum in the families with tumor incidence and spectrum in the population (data from the population - based Basel Cancer Registry). A nonrandom distribution of cancer in first-degree relatives of cancer patients and significant familial cancer aggregations point to underlying genetic mechanisms. The association of cancer and minor anomalies in children points to common mechanisms of carcinogenesis and teratogenesis. Laboratory investigations revealed an impaired DNA-repair synthesis in lymphocytes of breast cancer patients and their relatives. Patients and their relatives are counselled. They show interest and cooperate well. An early detection program is being developed in colorectal cancer. Administrative work is centrally organized and the screening work is performed by the family physicians.     

Very high incidence of familial colorectal cancer in Newfoundland: a comparison with Ontario and 13 other population-based studies

Newfoundland has the highest rate of colorectal cancer (CRC) of any Canadian province. In order to investigate the factors, especially genetic components, responsible for CRC we established the Newfoundland Colorectal Cancer Registry. In a 5-year period we examined every case of CRC diagnosed under the age of 75 years and obtained consent from 730 cases. Careful analysis of family history was used to assign a familial cancer risk, based on established criteria. We observed that 3.7% of CRC cases came from families meeting the Amsterdam II criteria and a further 0.9% of cases involved familial adenomatous polyposis (FAP). An additional 43% of cases met one or more of the revised Bethesda criteria and 31% of all cases had a first-degree relative affected with CRC. We compared the Newfoundland data with data from the province of Ontario, where the same recruitment and risk-assessment criteria were used. In all categories, the indicators of familial risk were significantly higher in Newfoundland. These data were also compared to results published from 13 other population-based studies worldwide. In every category the proportion of Newfoundland cases meeting the criteria was higher than in any other population. The mean differences were: 3.5-fold greater for FAP, 2.8-fold higher for Amsterdam criteria, 2.0-fold higher for Bethesda criteria and 1.9-fold higher for the number of affected first-degree relatives. We conclude that the high incidence of CRC in Newfoundland may be attributable to genetic, or at least familial, factors. In the high-risk families we provide evidence for the involvement of founder mutations in the APC and MSH2 genes. Drs. Parfrey and Younghusband contributed equally to this paper.     

Multiple primary colorectal cancer: Individual or familial predisposition?

Colorectal carcinoma (CRC) is one of the most frequent cancers. Along the surface of the large bowel, several foci of CRC may appear simultaneously or over the time. The development of at least two different tumours has been defined as multiple primary CRC (MPCRC): When more than one tumour is diagnosed at the same time, it is known as synchronous CRC (SCRC), while when a second neoplasm is diagnosed some time after the resection and/or diagnosis of the first lesion, it is called metachronous CRC (MCRC). Multiple issues can promote the development of MPCRC, ranging from different personal factors, such as environmental exposure, to familial predisposition due to hereditary factors. However, most studies do not distinguish this dichotomy. High- and low-pentrance genetic variants are involved in MPCRC. An increased risk for MPCRC has been described in Lynch syndrome, familial adenomatous polyposis, and serrated polyposis. Non-syndromic familial CRCs should also be considered as risk factors for MPCRC. Environmental factors can promote damage to colon mucosae that enable the concurrence of MPCRC. Epigenetics are thought to play a major role in the carcinogenesis of sporadic MPCRC. The methylation state of the DNA depends on multiple environmental factors (e.g., smoking and eating foods cooked at high temperatures), and this can contribute to increasing the MPCRC rate. Certain clinical features may also suggest individual predisposition for MPCRC. Different etiopathogenic factors are suspected to be involved in SCRC and MCRC, and different familial vs individual factors may be implicated. MCRC seems to follow a familial pattern, whereas individual factors are more important in SCRC. Further studies must be carried out to know the molecular basis of risks for MPCRC in order to modify, if necessary, its clinical management, especially from a preventive point of view.     

Identification of predictive factors for the occurrence of predisposing MLH1 and MSH2 germline mutations among Sardinian patients with colorectal carcinoma

Factors predictive of carrying MLH1 and MSH2 germline mutations in patients with colorectal cancer (CRC) are as yet unknown. The aim of this population-based study, was to further define the role of MLH1/MSH2 mutations through an evaluation clinic program with 362 consecutive Sardinian CRC patients. Eight MLH1/MSH2 germline mutations were detected in 21 (6%) patients. Examining family cancer history, MLH1/MSH2 mutations were found in 14/48 (29.2%) probands from CRC families and, among them, in 10/13 (76.9%) families fulfilling the Amsterdam criteria. The patients with low familial recurrence (two CRCs in the family) presented a much lower frequency of MLH1/MSH2 mutations (2/55; 3.6%). Significantly higher rates of MLH1/MSH2 mutations were found in patients with age of onset 45 years (P=0.012) or with 3 affected family members (P=0.009). While no significant predictive value was found for the presence of endometrial cancer within the family, earlier age of diagnosis and/or familial CRC recurrence should be considered as strong predictors for the occurrence of MLH1/MSH2 mutations, and therefore useful in recommending CRC patients for genetic testing.     

遗传性非息肉病结直肠癌：附3个家族报道

目的 探讨遗传性非息肉病结直肠癌(hereditary nonpolyposis colerectal cancer,HNPCC)的特有诊断、治疗、随访及临床特征.方法 对3个有HNPCC特征的家族进行分析.结果3个HNPCC家族中有9例大肠癌及2例合并子宫内膜癌,共有大肠癌15处(其中5例为多原发大肠癌),中位发病年龄为38岁.结论HN-PCC具有发病年龄轻、近侧结肠癌多见、同时或异时大肠癌比例高及易发生其他器官癌的特点.对HNPCC患者及其亲属进行密切随访和定期检测具有早期诊断的重要意义.