Methylated SEPTIN9 plasma test for colorectal cancer detection may be applicable to Lynch syndrome.

OBJECTIVE: The plasma-based methylated SEPTIN9 (mSEPT9) is a colorectal cancer (CRC) screening test for adults aged 50-75 years who are at average risk for CRC and have refused colonoscopy or faecal-based screening tests. The applicability of mSEPT9 for high-risk persons with Lynch syndrome (LS), the most common hereditary CRC condition, has not been assessed. This study sought preliminary evidence for the utility of mSEPT9 for CRC detection in LS. DESIGN: Firstly, SEPT9 methylation was measured in LS-associated CRC, advanced adenoma, and subject-matched normal colorectal mucosa tissues by pyrosequencing. Secondly, to detect mSEPT9 as circulating tumor DNA, the plasma-based mSEPT9 test was retrospectively evaluated in LS subjects using the Epi proColon 2.0 CE assay adapted for 1mL plasma using the "1/1 algorithm". LS case groups included 20 peri-surgical cases with acolonoscopy-based diagnosis of CRC (stages I-IV), 13 post-surgical metastatic CRC, and 17 pre-diagnosis cases. The control group comprised 31 cancer-free LS subjects. RESULTS: Differential hypermethylation was found in 97.3% (36/37) of primary CRC and 90.0% (18/20) of advanced adenomas, showing LS-associated neoplasia frequently produce the mSEPT9 biomarker. Sensitivity of plasma mSEPT9 to detect CRC was 70.0% (95% CI, 48%-88%)in cases with a colonoscopy-based CRC diagnosis and 92.3% (95% CI, 64%-100%) inpost-surgical metastatic cases. In pre-diagnosis cases, plasma mSEPT9 was detected within two months prior to colonoscopy-based CRC diagnosis in 3/5 cases. Specificity in controls was 100% (95% CI 89%-100%). CONCLUSION: These preliminary findings suggest mSEPT9 may demonstrate similar diagnostic performance characteristics in LS as in the average-risk population, warranting a well-powered prospective case-control study.

Phenotypic and genotypic heterogeneity of Lynch syndrome: a complex diagnostic challenge.

Lynch syndrome is the hereditary disorder that most frequently predisposes to colorectal cancer as well as predisposing to a number of extracolonic cancers, most prominently endometrial cancer. It is caused by germline mutations in the mismatch repair genes. Both its phenotype and genotype show marked heterogeneity. This review gives a historical overview of the syndrome, its heterogeneity, its genomic landscape, and its implications for complex diagnosis, genetic counseling and putative implications for immunotherapy.

Colonoscopy and chromoscopy in hereditary colorectal cancer syndromes.

With hereditary colorectal cancer prevention studies it is difficult to demonstrate reduced mortality. Large populations are needed with well characterized genetics followed over a long period of time. Those studies do exist for standard white light colonoscopy surveillance in Lynch syndrome, but not for newer technologies including chromoscopy. For these newer technologies adenoma detection rate becomes the stand-in for mortality, and the assumption is made that surveillance efficacy impacts cancer occurrence. Though well-designed and important work exists in this area, the data do not support firm conclusions regarding the use of chromoscopy in Lynch syndrome.

Genetics, biomarkers, hereditary cancer syndrome diagnosis, heterogeneity and treatment: a review.

OPINION STATEMENT: Molecular genetic pathways that drive the phenotypic and genotypic heterogeneity of hereditary colorectal cancer also can affect response to chemotherapy and chemoprevention. These mutations also can alter patients' response to therapy. Environmental differences can affect this highly complex conundrum. We will use Lynch syndrome as a model to explore this issue. However, to begin with, after more than a century of documentation, we must ask what is meant by the eponym "Lynch syndrome". Germline mutations may act as drivers of chemoprevention and chemotherapy and therein may act positively or conversely they may have a negative effect in terms of inhibiting the inactivation of cancer-causing germline mutations. A relatively new field of hereditary cancer therapeutics has significantly impacted cancer care, from the standpoint of the sensitivity or resistance to a particular form of chemotherapy and/or chemoprevention. The question for the diagnostician and therapist must always concern what is the best possible management approach for the patient, particularly when he or she harbors a cancer-causing germline mutation, which, in this case, causes Lynch syndrome. Continued molecular genetic research might yield a more tailored effective treatment for Lynch syndrome. The ultimate goal of such hereditary oncologic research is to better understand the mutation's therapeutic task, namely, its potential to benefit the patient in terms of its treatment goal, thereby fulfilling the essence of personalized medicine. However, this goal may be exceedingly complicated. For example, in the natural clinical and molecular genetic history of hereditary forms of cancer, there will be a predominance of early-onset cancers of multiple anatomic sites. In our Lynch syndrome model, these will be most commonly colorectal, endometrial, and ovarian cancer. Attention must initially be focused upon cancer's early age of onset coupled with the tendency to multiple primary cancers so that, in the case of CRC, colonoscopic screening must be initiated by age 20-25 years and repeated every other year until age 40 years and then annually thereafter. However, screening will be of limited efficacy in the gynecologic cancers (endometrial and ovarian) so that once the family is completed, particularly by age 35-40 years, careful attention must be given to the option of prophylactic hysterectomy and bilateral salpingo-oophorectomy. Given issues of tumor heterogeneity, selected Lynch syndrome families may show an excess of urologic cancers or cancers of the small bowel, and highly targeted screening should be given serious consideration for these as well as cancers of other anatomic sites in such high-risk, cancer-prone patients.

Acute appendicitis: a potential complication of video capsule endoscopy.

A 69-year-old man presented to our emergency room with malena and symptoms suggestive of anaemia. He was on chronic anticoagulation with warfarin for a mechanical aortic valve. He was haemodynamically stable. Laboratory investigations revealed a low haemoglobin level of 7.1 g/dL and a low-ferritin level of 6 ng/dL suggesting chronic gastrointestinal bleeding. Oesophagogastroduodenoscopy and colonoscopy were performed to identify the source of bleeding but were unfruitful. Video capsule endoscopy was performed. Fifteen hours after ingesting the capsule endoscope, the patient started having severe abdominal pain, nausea and vomiting. Abdominal X-ray did not show any bowel perforation. CT of the abdomen revealed impaction of the capsule endoscope at the appendiceal orifice and an inflamed appendix. The patient underwent laparoscopic appendectomy and made a good recovery.

Serrated polyposis: the last (or only the latest?) frontier of familial polyposis?

Serrated polyps are thought to be precursors of ~15% of colorectal cancers and clinical criteria for a serrated polyposis (SP) syndrome have been proposed. In this issue of American Journal of Gastroenterology, Win et al. report that family members of individuals who meet the clinical criteria for SP are at increased risk for colorectal and possibly pancreatic cancer. The important data presented by Win et al. strongly support the concept that familial SP exists and help define the patterns of risk in this syndrome. The paper also illustrates the difficulties of trying to define a genetic syndrome on the basis of largely retrospective clinical data and highlights the importance of efforts to define the genetic basis of familial SP and to study these families in a systematic, prospective manner.

Diagnosing lynch syndrome in absence of colorectal cancer.

There are many ways in which a diagnosis of Lynch syndrome can be made, most prominent of which is family history, presence of cancer, high microsatellite instability, immunohistochemistry, and a mismatch repair germline mutation. There are at least four molecular pathways for colorectal cancer carcinogenesis: 1) adenoma-carcinoma sequence; 2) hereditary microsatellite instability; 3) serrated pathway; 4) epidermal growth factor receptor. The answer to diagnosing Lynch syndrome in the absence of colorectal cancer may be partially based upon the phenotypic characteristics of the colonic polyps should they be identified at colonoscopy, specifically their phenotypic characteristics of location, size, histology, number, and age of polyp onset.

Making sense of missense in Lynch syndrome: the clinical perspective.

The DNA mismatch repair (MMR) system provides critical genetic housekeeping, and its failure is associated with tumorigenesis. Through distinct domains on the DNA MMR proteins, the system recognizes and repairs errors occurring during DNA synthesis, but signals apoptosis when the DNA damage cannot be repaired. Certain missense mutations in the MMR genes can selectively alter just one of these functions. This affects the clinical features of tumors associated with defective DNA MMR activity. New work reported by Xie et al. in this issue of the journal (beginning on page 1409) adds to the understanding of DNA MMR.

FAP, gastric cancer, and genetic counseling featuring children and young adults: a family study and review.

Familial adenomatous polyposis is a highly complex and multifaceted colorectal cancer prone disorder which is often significantly confounded by extracolonic cancers inclusive of gastric cancer, a significant problem in the Orient. Gastric cancer in familial adenomatous polyposis is heavily influenced by fundic gland polyps which are often so voluminous as to defy effective endoscopic surveillance. This study involves more than two decades of investigation of an attenuated familial adenomatous polyposis family where gastric cancer posed an early diagnostic problem because it was obscured by multiple fundic gland polyps. Fundic gland polyps are common in familial adenomatous polyposis and attenuated familial adenomatous polyposis and, if voluminous, may interfere with effective endoscopic gastric cancer surveillance. This family is believed to be the first of its type reported with focus upon education and genetic counseling in the setting of a family information service. Cancer control in familial adenomatous polyposis may be partially resolved through use of familial colorectal cancer registries, with greater attention to family history and its interpretation, genetic counseling, and clinical translation for diagnosis and management.

Familial pancreatic cancer.

Pancreatic cancer's high mortality rate equates closely with its incidence, thereby showing the need for development of biomarkers of its increased risk and a better understanding of its genetics, so that high-risk patients can be better targeted for screening and early potential lifesaving diagnosis. Its phenotypic and genotypic heterogeneity is extensive and requires careful scrutiny of its pattern of cancer associations, such as malignant melanoma associated with pancreatic cancer, in the familial atypical multiple mole melanoma syndrome, due to the CDKN2A germline mutation. This review is designed to depict several of the hereditary pancreatic cancer syndromes with particular attention given to the clinical application of this knowledge into improved control of pancreatic cancer.

Cannabinoid hyperemesis syndrome: clinical diagnosis of an underrecognised manifestation of chronic cannabis abuse.

Cannabis is a common drug of abuse that is associated with various long-term and short-term adverse effects. The nature of its association with vomiting after chronic abuse is obscure and is underrecognised by clinicians. In some patients this vomiting can take on a pattern similar to cyclic vomiting syndrome with a peculiar compulsive hot bathing pattern, which relieves intense feelings of nausea and accompanying symptoms. In this case report, we describe a twenty-two year-old-male with a history of chronic cannabis abuse presenting with recurrent vomiting, intense nausea and abdominal pain. In addition, the patient reported that the hot baths improved his symptoms during these episodes. Abstinence from cannabis led to resolution of the vomiting symptoms and abdominal pain. We conclude that in the setting of chronic cannabis abuse, patients presenting with chronic severe nausea and vomiting that can sometimes be accompanied by abdominal pain and compulsive hot bathing behaviour, in the absence of other obvious causes, a diagnosis of cannabinoid hyperemesis syndrome should be considered.

Bouveret syndrome and gallstone ileus.

Intestinal obstruction from gallstones is a rare complication of gallstone disease. These ectopic gallstones can cause obstruction anywhere from the duodenum to the colon and are accompanied by a cholecystoduodenal/enteric/colic fistula. We report an 81-year-old male who presented with gallstone obstruction of the duodenum who underwent attempted endoscopic fragmentation and extraction that eventually led to small bowel obstruction from an impacted fragment of the stone. He underwent successful enterolithotomy and has been asymptomatic from the cholecystoduodenal fistula. Surgery is the gold standard for the treatment of this condition but the extent of the operation remains a matter of debate.