Familial risk and colorectal cancer

Noninvasive prenatal screening and maternal malignancy: role of imaging

Noninvasive prenatal screening (NIPS) tests for fetal chromosomal anomalies through maternal blood sampling. It is becoming widely available and standard of care for pregnant women in many countries. It is performed in the first trimester of pregnancy, usually between 9 and 12 weeks. Fragments of fetal cell-free deoxyribonucleic acid (DNA) floating in maternal plasma are detected and analyzed by this test to assess for chromosomal aberrations. Similarly, maternal tumor-derived cell-free DNA (ctDNA) released from the tumor cells also circulates in the plasma. Hence, the presence of genomic anomalies originating from maternal tumor-derived DNA may be detected on the NIPS-based fetal risk assessment in pregnant patients. Presence of multiple aneuploidies or autosomal monosomies are the most commonly reported NIPS abnormalities detected with occult maternal malignancies. When such results are received, the search for an occult maternal malignancy begins, in which imaging plays a crucial role. The most commonly detected malignancies via NIPS are leukemia, lymphoma, breast and colon cancers. Ultrasound is a reasonable radiation-free modality for imaging during pregnancy, specially when there are localizing symptoms or findings, such as palpable lumps. While there are no consensus guidelines on the imaging evaluation for these patients, when there are no localizing symptoms or clinically palpable findings, whole body MRI is recommended as the radiation-free modality of choice to search for an occult malignancy. Based on clinical symptoms, practice patterns, and available resources, breast ultrasound, chest radiographs, and targeted ultrasound evaluations can also be performed initially or as a follow-up for MRI findings. CT is reserved for exceptional circumstances due to its higher radiation dose. This article intends to increase awareness of this rare but stressful clinical scenario and guide imaging evaluation for occult malignancy detected via NIPS during pregnancy.

EP4 receptor as a novel promising therapeutic target in colon cancer

The most prevalent malignancy that can occur in the gastrointestinal tract is colon cancer. The current treatment options for colon cancer patients include chemotherapy, surgery, radiotherapy, immunotherapy, and targeted therapy. Although the chance of curing the disease in the early stages is high, there is no cure for almost all patients with advanced and metastatic disease. It has been found that over-activation of cyclooxygenase 2 (COX-2), followed by the production of prostaglandin E2 (PGE2) in patients with colon cancer are significantly increased. The tumorigenic function of COX-2 is mainly due to its role in the production of PGE2. PGE2, as a main generated prostanoid, has an essential role in growth and survival of colon cancer cell's. PGE2 exerts various effects in colon cancer cells including enhanced expansion, angiogenesis, survival, invasion, and migration. The signaling of PGE2 via the EP4 receptor has been shown to induce colon tumorigenesis. Moreover, the expression levels of the EP4 receptor significantly affect tumor growth and development. Overexpression of EP4 by various mechanisms increases survival and tumor vasculature in colon cancer cells. It seems that the pathway starting with COX2, continuing with PGE2, and ending with EP4 can promote the spread and growth of colon cancer. Therefore, targeting the COX-2/PGE2/EP4 axis can be considered as a worthy therapeutic approach to treat colon cancer. In this review, we have examined the role and different mechanisms that the EP4 receptor is involved in the development of colon cancer.

Tumor budding for predicting prognosis of resected rectum cancer after neoadjuvant treatment

BACKGROUND

Rectum cancer is a type of colorectal cancer. Its etiology and etiopathogenesis are similar to other colon diseases. We aimed to evaluate the tumor budding for predicting prognosis of resected rectum cancer patients.

METHODS

We retrospectively collected the data of 75 operated rectum adenocarcinoma patients who were treated neoadjuvant chemoradiotherapy between 2013 and 2018 in Umraniye Research and Training Hospital and Acıbadem University Medical Oncology Outpatient Clinic. Tumor budding was investigated as a prognostic factor for disease-free survival.

RESULTS

This study included 75 rectum cancer patients and 51 were male (68%). Median age was 56 (range 19 to 77 years). There were 29 (39%) and 46 (61%) patients in tumor budding low-intermediate and high groups respectively. In multivariate analysis, tumor budding was found to be an independent prognostic factor for disease-free survival (p = 0.00).

CONCLUSIONS

According to our study, having high tumor budding suggests a high likelihood of relapse. Therefore, we might need additional follow-up protocol in these patients.

No evidence that associations of incident, sporadic colorectal adenoma with its major modifiable risk factors differ by chromosome 8q24 region rs6983267 genotype

A single nucleotide polymorphism (SNP), rs6983267, in the chromosome 8q24 region, has been associated with higher risk for colorectal neoplasms, but its relation to carcinogenic mechanisms is unclear. To investigate whether associations of colorectal adenoma with its major modifiable risk factors differ according to rs6983267 genotype, we performed a pooled analysis of the White participants (n = 401 cases, 518 controls) from three colonoscopy-based, case-control studies of incident, sporadic colorectal adenoma conducted between 1991 and 2002. There was a statistically significant direct association of rs6983267 with colorectal adenoma that was consistent with those in previous reports. We found no clear indications that rs6983267 impacts the association of colorectal adenomas with the following risk factors: physical activity, body mass index (BMI), nonsteroidal anti-inflammatory drug (NSAID) use, tobacco or alcohol use, hormone replacement therapy among women, blood 25-OH-vitamin D3 levels, oxidative balance, or total energy, calcium, red meat, vegetable and fruit, and folate intakes. These findings, together with previously reported null results on 8q24-environment interactions for colorectal cancer, suggest that associations of colorectal adenoma with its major modifiable risk factors may not differ according to chromosome 8q24 region rs6983267 genotype.

Colon cancer screening in women

Colorectal cancer is the third leading cause of cancer-related deaths in women. Colorectal cancer is a preventable disease with accepted screening modalities that have been proven to save lives. As women are more likely than men to develop right-sided colon cancers, colonoscopy is the preferred screening test in women. Currently, women are less likely to undergo colorectal cancer screening than men. Frank discussions addressing the fear or embarrassment of endoscopic screening are important in helping women overcome these barriers. Enhanced education of both practitioners and patients targeted to improve colorectal cancer screening adherence will improve early diagnosis and patient survival.

Q&A on diagnosis, screening and follow-up of colorectal neoplasia

The impressive and brisk evolution of medical science prevents many physicians from a thorough update on all the research fields. Colorectal cancer diagnosis, screening and follow-up is well known to require a multi-disciplinary approach, as it is faced by several specialties such as primary care physicians, gastroenterologists, non-gastroenterologist internists, radiologists and surgeons. To address this issue in a mutual perspective, we focused on the main points of the epidemiology, diagnosis, screening and follow-up of colorectal neoplasia by using a simple "Question & Answers" structure.

Environmental influences on the high mortality from colorectal cancer in African Americans

Colon cancer is the second leading cause of cancer related death in American adults. The incidence and mortality are highest in African Americans (AAs) (incidence: 52 per 100,000) and lowest in American Hispanics (37 per 100,000). Comparative studies with Native Africans (<5 per 100,000) suggest that genetic susceptibility is an unlikely explanation and that environmental influences are to blame. Studies have suggested that risk is high because of excessive intakes of animal meat and fat products and differences in colonic bacterial metabolism, and that preventative and therapeutic management of colon cancer is compromised by the development of greater tumour virulence possibly resulting from disparities in educational and insurance status, screening behaviour, treatment patterns, social support, and access to and use of health care facilities. It should be possible to reduce the unacceptably higher rates of morbidity and mortality from colon cancer in AAs by dietary and lifestyle changes aimed at suppressing excessive intakes of animal meat and fat products, increasing the consumption of fresh fruit and vegetables, controlling energy balance, and by developing strategies to improve the availability, use and accessibility to health care resources.

Impact of the cyclin D1 A870G polymorphism on susceptibility to sporadic colorectal cancer in Taiwan

PURPOSE

Cyclin D1 is a regulatory protein involved in the cell cycle of both normal and neoplastic cells. Polymorphism of this gene at codon 242 in exon 4 has impacts on risk of the early-age onset in several malignant neoplasms, including colorectal cancer. This investigation was designed to evaluate the effect of cyclin D1 gene polymorphism on the risk of colorectal cancer in Chinese migrants of the Taiwanese population.

METHODS

We enrolled 831 primary sporadic colorectal cancer patients as the study group and 1,052 age-gender matched healthy individuals as the control group (1,883 total cases) for present study. Cyclin D1 genotypes (AA, AG, GG) were determined using PCR-RFLP analysis on genomic DNA.

RESULTS

The frequency of G allele was 39.89 percent and 40.96 percent in the study group and the control group, respectively (P = 0.02). The patients were divided into three age groups for statistical analysis. The younger male patients had a higher frequency of AA/AG genotype compared with the controls (odds ratio, 2.75; 95 percent confidence interval, 1-7.9). The effect of AA/AG genotype on colorectal cancer risk was statistically significant for male patients (odds ratio, 1.34; 95 percent confidence interval, 1.04-1.72), but such phenomenon was not observed in female patients.

CONCLUSIONS

Our study suggests that the effect of cyclin D1 gene polymorphism on colorectal cancer risk is only observed in males and AA/AG genotype of cyclin D1 gene is associated with a higher risk of colorectal cancer in the younger patients within the Taiwanese population.

Assay validation for identification of hereditary nonpolyposis colon cancer-causing mutations in mismatch repair genes MLH1, MSH2, and MSH6

Hereditary nonpolyposis colon cancer (HNPCC, Online Mendelian Inheritance in Man (OMIM) 114500) is an autosomal dominant disorder that is genetically heterogeneous because of underlying mutations in mismatch repair genes, primarily MLH1, MSH2, and MSH6. One challenge to correctly diagnosing HNPCC is that the large size of the causative genes makes identification of mutations both labor intensive and expensive. We evaluated the usefulness of denaturing high performance liquid chromatography (DHPLC) for scanning mismatch repair genes (MLH1, MSH2, and MSH6) for point mutations, small deletions, and insertions. Our assay consisted of 51 sets of primers designed to amplify all exons of these genes. All polymerase chain reaction reactions were amplified simultaneously using the same reaction conditions in a 96-well format. The amplified products were analyzed by DHPLC across a range of optimum temperatures for partial fragment denaturation based on the melting profile of each specific fragment. DNA specimens from 23 previously studied HNPCC patients were analyzed by DHPLC, and all mutations were correctly identified and confirmed by sequence analysis. Here, we present our validation studies of the DHPLC platform for HNPCC mutation analysis and compare its merits with other scanning technologies. This approach provides greater sensitivity and more directed molecular analysis for clinical testing in HNPCC.

Gastrointestinal, Pancreatic, and Hepatic Cancer During Pregnancy

Pregnancy affects the clinical presentation, evaluation, treatment, and prognosis of patients with gastrointestinal cancer. Pregnant patients may present with advanced gastrointestinal cancer as a result of delayed diagnosis, in part because of difficulty differentiating signs and symptoms of cancer from signs and symptoms of normal pregnancy. The approach to cancer surgery and chemotherapy must be modified in pregnant patients to minimize fetal and maternal risks. Because of these factors, women who develop gastrointestinal cancers during pregnancy seem to have a poor prognosis. This article focuses on cancers of the colon, stomach, pancreas, and liver that occur during pregnancy.

Biomarkers in molecular medicine: cancer detection and diagnosis

In spite of advances in diagnostics and therapeutics, cancer remains the second leading cause of death in the U.S. Successful cancer treatment depends not only on better therapies but also on improved methods to assess an individual's risk of developing cancer and to detect cancers at early stages when they can be more effectively treated. Current cancer diagnostic imaging methods are labor-intensive and expensive, especially for screening large asymptomatic populations. Effective screening strategies depend on methods that are noninvasive and detect cancers in their early stages of development. There is increasing interest and enthusiasm in molecular markers as tools for cancer detection and prognosis. It is hoped that newly discovered cancer biomarkers and advances in high-throughput technologies would revolutionize cancer therapies by improving cancer risk assessment, early detection, diagnosis, prognosis, and monitoring therapeutic response. These biomarkers will be used either as stand-alone tests or to complement existing imaging methods.

Prevalence of adenomas among young individuals at average risk for colorectal cancer

OBJECTIVES

We evaluated the prevalence and characteristics of adenomas in a young population not genetically predisposed for the development of colorectal cancer (CRC).

METHODS

The databases of the Dutch Hereditary Colorectal Cancer Registry were used. The study population included patients (n = 444) who had regular endoscopy until mutation analysis revealed they did not carry the (Adenomatous Polyposis Coli (APC)/Mismatch Repair) gene defect identified in their family.

RESULTS

At first colonoscopy (n = 342; 50% males, mean age 37 yr) a total of 19 adenomas (10 males, mean age 50 yr, range 24-91 yr) and two CRCs (2 males, age 49 and 72 yr) were identified, and at first sigmoidoscopy (n = 102; 53% males, mean age 29 yr) three adenomas (2 males, age 8, 40, and 41 yr) were found. A second colonoscopy was performed in 14 patients with, and in 162 patients without an adenoma. Three of 14 patients (21%) developed a new adenoma (all >50 yr) and 8 of 162 (5%) patients developed their first adenoma during follow-up. In the colonoscopy group, the cumulative proportion of patients free of adenomas at age 50 yr was 86%. Of all adenomas diagnosed during colonoscopy (n = 49), 65% were located distal from the flexura lienalis. Of the adenomas detected during all endoscopies (n = 53), 9.8% were > or =7 mm, 7.5% showed high-grade dysplasia, and 7.5% showed tubulovillous features.

CONCLUSIONS

On the basis of our findings during colonoscopy we conclude that the risk of developing adenomas/CRC in young individuals without genetic risk factors is low. Adenoma surveillance programs should focus on young individuals with a positive family (or personal) history for adenomas/CRC, or on individuals >50 yr.

[Extracolonic manifestations of familial adenomatous polyposis: incidence and impact on the disease outcome]

BACKGROUND

Familial adenomatous polyposis is a hereditary disease with autossomic and dominant features, frequently associated to many extracolonic manifestations.

AIM

To report extracolonic manifestations incidence and to analyze its impact on the disease's outcome.

PATIENTS AND METHODS

Revision of patient charts treated from 1977 to 2001, relating associated extracolonic manifestations and its complications.

RESULTS

Among 59 familial adenomatous polyposis patients, 23 (38,9%) presented some extracolonic manifestations at diagnosis or during follow-up. There were registered 37 different extracolonic manifestations (1.6 per patient). The most common manifestations were osteomas and congenital hypertrophy of the retinal pigment epithelium, diagnosed in 25% and 20% of the investigated patients, respectively. Other extracolonic manifestations were represented by upper digestive adenomas, epidermoid cysts, desmoid tumor (seven each), gastric cancer (three) and tireoid cancer (two). Desmoid-associated complications were reported in six patients, being intestinal obstruction in four and hidronephrosis in two; two deaths (28,5%) were registered.

CONCLUSIONS

Extracolonic manifestations incidence is high (40%) and may affect disease's outcome and patient's quality of life. For these reasons, the research, prevention and adequate treatment of extracolonic manifestations turn into vital importance in familial adenomatous polyposis patients.

Colon cancer during pregnancy

The medical community should become mobilized to diagnose colon cancer earlier in pregnancy to improve prognosis. The primary care physician or obstetrician should refer the pregnant patient with significant gastrointestinal complaints to the gastroenterologist for evaluation. Likewise, the gastroenterologist should be prepared to perform sigmoidoscopy, preferably without endoscopic medications, for significant lower gastrointestinal symptoms such as persistent rectal bleeding. Sigmoidoscopy is particularly sensitive in identifying colon cancer in pregnant patients because their cancers are usually distal and within reach of the sigmoidoscope.

Familial and inherited colorectal cancer: endoscopic screening and surveillance

Familial risk of colorectal cancer is very common. The high-risk inherited syndromes are well described and much is known about the genetics and the effectiveness of registration, endoscopic surveillance, and appropriate intervention in these patients. The inherited syndromes, however, are extremely rare. There is a large group of patients in our population who can benefit from risk stratification based on the number of their relatives with colon cancer or adenomas and the age at which those relatives developed neoplasm. The GI endoscopist has a vital role in recommending and providing colonoscopic screening for this large group of patients.

Cancer genetics in oncology practice

Cancer is a genetic disease caused by the progressive accumulation of mutations in critical genes that control cell growth and differentiation. Completion of the Human Genome Project promises to revolutionize the practice of Medicine, especially Oncology care. The tremendous gains in the knowledge of the structure and function of human genes will surely impact the diagnosis, prognosis and treatment of cancer. Moreover, it will lead to more effective cancer control through the use of genetics to quantify individual cancer risks. This article reviews the current status of genetic testing and counseling for cancer risk assessment and will suggest a framework for integrating such counseling into oncology practice.

Hereditary non-polyposis colorectal cancer: an updated review

INTRODUCTION

Colorectal cancer is the commonest cause of death due to malignancy in non-smokers in the western countries. The two main hereditary types of colorectal cancer are familial adenomatous polyposis (FAP) and hereditary non-polyposis colorectal cancer (HNPCC), constituting approximately 10% of all cases of colorectal cancer. The main aim of this review is to reappraise the current advances in the genetics and diagnosis of HNPCC.

METHODS

A Medline search was carried out to identify papers published from 1970 to 1999 on HNPCC. Embase and Cochrane databases were also searched. Reference lists of retrieved articles were carefully searched for additional articles.

RESULTS AND CONCLUSIONS

Recent technological advances in the genetics of HNPCC have refined the criteria for diagnosis and management of HNPCC, however current policies regarding the testing of pedigrees are not clearly established. We believe that with the rapid development in this area definitive clinical guidelines will need to be available in future for the management of HNPCC.

Families at risk for colorectal cancer: risk assessment and genetic testing

As befits a common cancer, a family history of colorectal cancer (CRC) is reported by about 10% of individuals. The discovery of the genetic basis of hereditary nonpolyposis CRC and familial adenomatous polyposis has opened up the possibility for determining genetic predisposition to CRC in asymptomatic family members of affected cases. This article reviews the information needed for accurate risk assessment for those with a family history of CRC. Screening recommendations and the current status of genetic testing, including review of available tests such as microsatellite instability, immunohistochemistry for hMSH2 and hMLH1, testing for I1307K, and gene testing for germline mutations in hMSH2 and hMLH1 are discussed. At the current time, reliable, informative genetic testing, capable of application to broad segments of the population, is an unrealized goal. But as the methodology for testing improves and as better appreciation of the significance and meaning of a positive or negative test result ensues conditions for increased use of genetic testing could emerge.

Familial association

Familial risk of colon cancer is a commonly encountered issue, involving both rare inherited syndromes of colon cancer and common familial clustering of cases. The genes that give rise to the rare syndromes of FAP and HNPCC are now known and current research is addressing the cellular mechanisms of these genes and the proper application of genetic testing in families with one of the syndromes. Common familial clustering of cases appears to arise from an interaction of mildly to moderately severe inherited susceptibility factors with certain environmental factors to give rise to adenomatous polyps and then finally colorectal cancer. Research in this area involves identification of these purportedly more common susceptibility genes, and determination of how each interacts with environmental factors to give rise to polyps and cancer. Optimal application of varying degrees of familial risk to screening strategies is also being determined.

Mouse models for colorectal cancer

Colorectal cancer (CRC) is one of the most common cancers in the Western world. Much has been learned about colorectal cancer from human inherited syndromes, such as familial adenomatous polyposis (FAP) and hereditary non-polyposis colorectal cancer (HNPCC). Mouse models for CRC were generated by introducing mutations into the mouse genes, whose human counterparts were implicated in the onset and progression of CRC. Central among these are mice carrying mutations in the Adenomatous polyposis coli (Apc) gene. Although most of these Apc mutations share some common phenotypes as homozygous embryonic lethality and tumor predisposition, the severity of the tumor predisposition is variable. Mice with mutations in the mismatch repair genes, Msh2 and Mlh1, exhibit a mismatch repair defect and are predisposed to developing gastrointestinal cancer, lymphomas and tumors of other organ systems. Mice carrying a mutation in the Pms2 gene are predisposed to lymphomas and other tumors. Mice with a mutation in the Msh6 gene have a defect in base mismatch repair and show a tumor predisposition phenotype. Mice with mutations in Mlh1, Pms2 and Msh5 have defects in meiosis suggesting unique roles for these genes in gametogenesis.

Mortality in male and female capacitor workers exposed to polychlorinated biphenyls

A mortality study was conducted in workers with at least 90 days' exposure to polychlorinated biphenyls (PCBs) between 1946 and 1977. Vital status was established for 98.7% of the 7075 workers studied. In hourly male workers, the mortality from all cancers was significantly below expected (standardized mortality ratio [SMR] = 81; 95% confidence interval [CI], = 68 to 97) and comparable to expected (SMR = 110; 95% CI, 93 to 129) in hourly female workers. No significant elevations in mortality for any site-specific cause were found in the hourly cohort. All-cancer mortality was significantly below expected in salaried males (SMR = 69; 95% CI, 52 to 90) and comparable to expected in salaried females (SMR = 75; 95% CI, 45 to 118). No significant elevations were seen in the most highly exposed workers, nor did SMRs increase with length of cumulative employment and latency. None of the previously reported specific excesses in cancer mortality were seen. This is the largest cohort of male and female workers exposed to PCBs. The lack of any significant elevations in the site-specific cancer mortality of the production workers adds important information about human health effects of PCBs.

Colon cancer during pregnancy. The gastroenterologist's perspective

Colon cancer during pregnancy is uncommon but not rare, with an estimated incidence of several hundred cases per year in the United States. This type of cancer tends to have a poor prognosis that is attributable to delays in diagnosis and advanced disease at diagnosis. The diagnosis frequently is delayed because symptoms of colon cancer, such as rectal bleeding, nausea and vomiting, and constipation, often are attributed to normal pregnancy or minor complications of pregnancy. Pregnancy affects the diagnostic evaluation and therapy of colon cancer because of fetal risks of diagnostic tests and therapy. Appropriate medical evaluation of significant lower gastrointestinal complaints during pregnancy can lead to an earlier and improved diagnosis.