Management of colorectal polyps: is all the effort worthwhile?

Mapping the Diverse and Inclusive Future of Parkinson's Disease Genetics and Its Widespread Impact

Over the last decades, genetics has been the engine that has pushed us along on our voyage to understand the etiology of Parkinson's disease (PD). Although a large number of risk loci and causative mutations for PD have been identified, it is clear that much more needs to be done to solve the missing heritability mystery. Despite remarkable efforts, as a field, we have failed in terms of diversity and inclusivity. The vast majority of genetic studies in PD have focused on individuals of European ancestry, leading to a gap of knowledge on the existing genetic differences across populations and PD as a whole. As we move forward, shedding light on the genetic architecture contributing to PD in non-European populations is essential, and will provide novel insight into the generalized genetic map of the disease. In this review, we discuss how better representation of understudied ancestral groups in PD genetics research requires addressing and resolving all the challenges that hinder the inclusion of these populations. We further provide an overview of PD genetics in the clinics, covering the current challenges and limitations of genetic testing and counseling. Finally, we describe the impact of worldwide collaborative initiatives in the field, shaping the future of the new era of PD genetics as we advance in our understanding of the genetic architecture of PD.

Roles of forkhead box O (FoxO) transcription factors in neurodegenerative diseases: A panoramic view

Neurodegenerative diseases (NDDs), which are among the most important aging-related diseases, are typically characterized by neuronal damage and a progressive impairment in neurological function during aging. Few effective therapeutic targets for NDDs have been revealed; thus, an understanding of the pathogenesis of NDDs is important. Forkhead box O (FoxO) transcription factors have been implicated in the mechanisms regulating aging and longevity. The functions of FoxOs are regulated by diverse post-translational modifications (e.g., phosphorylation, acetylation, ubiquitination, methylation and glycosylation). FoxOs exert both detrimental and protective effects on NDDs. Therefore, an understanding of the precise function of FoxOs in NDDs will be helpful for developing appropriate treatment strategies. In this review, we first introduce the post-translational modifications of FoxOs. Next, the regulation of FoxO expression and post-translational modifications in the central nervous system (CNS) is described. Afterwards, we analyze and address the important roles of FoxOs in NDDs. Finally, novel potential directions of future FoxO research in NDDs are discussed. This review recapitulates essential facts and questions about the promise of FoxOs in treating NDDs, and it will likely be important for the design of further basic studies and to realize the potential for FoxOs as therapeutic targets in NDDs.

Serrated adenomas of the appendix

AIMS

A review of the literature indicated that only one case of serrated adenoma of the appendix has been recorded. The aim was to explore the possible occurrence of serrated adenomas of the appendix at the department of pathology, Karolinska Institute and University Hospital, Stockholm, Sweden.

METHODS

Between January 1993 and December 2003, 38 non-carcinoid, non-neoplastic, or neoplastic polyps or tumours of the appendix were surgically removed at this hospital. All filed histological sections (haematoxylin and eosin stained) were reviewed.

RESULTS

Of the 38 lesions, four were hyperplastic polyps, 10 serrated adenomas, six villous adenomas, and the remaining eight mucinous adenocarcinomas without a remnant adenoma. Serrated adenomas accounted for six of the 11 adenomas without invasion, and four of the 15 adenomas with invasive carcinoma. At the time of surgical resection, four of the 10 serrated adenomas had evolved into invasive carcinomas, in addition to 11 of the 16 villous adenomas.

CONCLUSIONS

Serrated and villous adenomas of the appendix appear to be highly aggressive lesions, more aggressive than similar adenomas in the colon and rectum. Of the seven cases with a hyperplastic polyp, one concurred with a serrated adenoma, two with a serrated adenoma having an invasive carcinoma, and one with invasive carcinoma without a remnant adenomatous structure. At present, there is an increased awareness that some hyperplastic polyps of the colon and rectum may evolve into serrated adenomas. Whether this pathway is also valid for the appendix vermiformis should be investigated in a larger number of cases.

Lewis antigens and argyrophilic nucleolar organizer regions staining for assessment of potential malignancy of adenomatous polyps of the gastrointestinal tract in children

Adenomatous polyps (AP) of the gastrointestinal tract in children are very rare. Because of their potential malignancy, they are of great clinical importance. There is little experience in the management of children with AP. The immunohistochemical expression of the Lewis blood group antigens (BGA) (sialosyl-Le(a), Le(a), Leb, Le(x), and Le(y)) and the number of activated nucleoli with the silver staining method for nucleolar organizer regions (AgNORs) were studied in two children with AP. In a girl with isolated AP of the stomach and colon, it was found that antigens Le(b) and s-Le(a) were expressed extensively in the gastric adenoma, and sialosyl-Le(a) throughout the entire length of the rectal adenoma crypts, but in the AgNORs stain the number of nucleoli ranged from two to four, evidencing changes of a benign character. In the case of familial adenomatous polyposis diagnosed in a 9-year-old boy, in some colonic adenomas the number of activated nucleoli was greater than five, and the Le(b) antigen was expressed in superficial epithelial cells in one of the adenomas. Also, extensive expression of antigens Le(y) and s-Le(a) throughout the entire length of the crypt in another polyp removed was observed. We believe that immunohistochemical study of the intensity and extent of the expression of Lewis BGA in the polyp tissue simultaneously with the determination of the number of activated nucleoli by the AgNORs staining method can be helpful in better analysis of cytological risk factors of a malignant transformation.

Colorectal polyps and their relationship to cancer

Autosomal dominant, familial forms of colorectal adenocarcinoma are recognized, but more than 90% of cases are sporadic. Most familial and sporadic cases arise through malignant transformation of benign adenomas in a process known as the adenoma-to-carcinoma sequence. Adenomas are classified histologically as tubular, tubulovillous, or villous. As a neoplasm, adenomas all manifest mild, moderate, or severe dysplasia. The majority (> 90%) of adenomas are small (< 1 cm in diameter) and do not progress. Risk factors for carcinomatous progression include the presence of multiple adenomas, size greater than or equal to 1 cm, and villous histology or severe dysplasia in adenomas of any size. The adenoma-to-carcinoma sequence advances through the accumulation of lesions involving multiple genes. It appears that similar molecular genetic mechanisms are involved in familial and sporadic forms of colorectal neoplasia.

Transanal endoscopic microsurgery in large, sessile adenomas of the rectum. A 10-year experience

The clinical and long-term results of 286 cases encountered from 1983 to 1993 in our Department of Surgery regarding the local excision of large, sessile rectal adenomas (> 2 cm2) by the endoscopic surgical method and the influence of this selected series of adenomas on age, sex, size, grade of dysplasia, and architecture are subjects of this study. Histologically proven rectal carcinomas as well as non-neoplastic polyps were excluded from this trial. Early postoperative complications amounted to 3.4%. The 1-year and 5-year recurrence rates +/- SE of adenomas were 1.2 +/- 0.7% and 7.0 +/- 1.9%, respectively. Remarkably, there was no significant relationship between the histological type of the adenoma and the grade of dysplasia nor between the size and grade of dysplasia. However, there was a significant relationship between the size and histological type of the adenoma (P < 0.01). With the endoscopic minimal-invasive system, we are able to achieve a superior rate of recurrence compared to any other local treatment as well as a more favorable operative result compared to extensive surgical procedures.

Does colonoscopic polypectomy reduce the incidence of colorectal carcinoma?

The study's objective was to examine whether there is evidence that colonoscopic polypectomy reduces the incidence of colorectal cancer. The records of all patients who underwent colonoscopic polypectomy by a single surgeon between 1974 and 1991 were reviewed. Patients with colorectal cancer diagnosed at the initial colonoscopy, with a history of colorectal cancer, inflammatory bowel disease or familial adenomatous polyposis or with only hyperplastic polyps were excluded. There were 1008 remaining patients, of whom 645 have attended at least one follow-up colonoscopic examination, and these 645 patients from the basis of the study, because the incidence of cancer is known exactly in this group. The mean period of follow up was 4.4 years and the mean number of follow-up colonoscopic examinations was 2.2. There was a total of 2847 person-years of colonoscopic follow up. The expected incidence of cancer, age and sex adjusted, is calculated using Australian epidemiological figures. The observed incidence of cancer was 3 cases (all asymptomatic) per 2847 person-years, which is indistinguishable from the general population's risk of 3.75 cases per 2847 person-years. Analysis of previous publications suggests that patients with adenomas are at an increased risk of developing colorectal cancer of about 2.5 times the general population's risk. If correct, then the observed incidence of 3 cases per 2847 person-years is less than the expected incidence of 9.4 cases per 2847 person-years. This analysis suggests colonoscopic polypectomy does reduce the incidence of colorectal cancer.

Patient characteristics and pathology in colorectal adenomas removed by colonoscopic polypectomy

Between September 1981 and August 1987 420 patients with 565 adenomas underwent colonoscopic polypectomy to produce a 'clean colon'. Data from these patients were analysed to identify associations between patient characteristics (age and sex), polyp characteristics (site, size, shape, multiplicity and villous content) and the degree of dysplasia in the index adenoma. In univariate analysis, severe dysplasia in the index adenoma was significantly but weakly associated with size (> or = 10 mm), peduncular shape and villous architecture. Logistic regression confirmed an independent effect only from villous architecture. These findings suggest that it is unlikely that strong predictors of a patient developing a metachronous adenoma or colorectal cancer can be identified on the basis of an index adenoma found at initial colonoscopy. These patients will continue to be followed to investigate this question.

A case-control study of screening sigmoidoscopy and mortality from colorectal cancer

BACKGROUND

The efficacy of sigmoidoscopic screening in reducing mortality from colorectal cancer remains uncertain. A randomized trial would be ideal for clarifying this issue but is very difficult to conduct. Case-control studies provide an alternative method of estimating the efficacy of screening sigmoidoscopy.

METHODS

Using data on the 261 members of the Kaiser Permanente Medical Care Program who died of cancer of the rectum or distal colon from 1971 to 1988, we examined the use of screening by rigid sigmoidoscopy during the 10 years before the diagnosis and compared it with the use of screening in 868 control subjects matched with the case subjects for age and sex.

RESULTS

Only 8.8 percent of the case subjects had undergone screening by sigmoidoscopy, as compared with 24.2 percent of the controls (matched odds ratio, 0.30; 95 percent confidence interval, 0.19 to 0.48). Adjustment for potential confounding factors increased the odds ratio to 0.41 (95 percent confidence interval, 0.25 to 0.69). The negative association was as strong when the most recent sigmoidoscopy was 9 to 10 years before diagnosis as it was when examinations were more recent. By contrast, for 268 subjects with fatal colon cancer above the reach of the sigmoidoscope and for 268 controls, the adjusted odds ratio was 0.96 (95 percent confidence interval, 0.61 to 1.50). The specificity of the negative association for cancer within the reach of the sigmoidoscope is consistent with a true efficacy of screening rather than a confounding by unmeasured selection factors.

CONCLUSIONS

Screening by sigmoidoscopy can reduce mortality from cancer of the rectum and distal colon. A screening once every 10 years may be nearly as efficacious as more frequent screening.

Gardner syndrome: study and follow-up of a family

A study is in progress of a family (Family P) with Gardner syndrome (familial adenomatous polyposis with extraintestinal manifestations-FAPG). Occult bone lesions of the jaws and ocular fundus lesions were found in a number of affected and at-risk relatives. In some, these "markers" were found early in life before the appearance of colonic polyps. Family P is remarkable for differences in expression of the gene manifested by differences in the age-at-onset of polyps of the colon, in number and size of polyps, and in occurrence of desmoids. These differences may explain why some at-risk relatives wisely followed medical surveillance plans while others, who lacked symptoms, failed to do so. Others without medical guidance undertook their own independent "treatment." As knowledge about extracolonic lesions has increased and surgical treatment for FAPG improved from the time the first affected member of Family P received her diagnosis in 1953, the outlook for survival has also improved. Family communication and that among professionals treating families with FAPG may be improved as worldwide Polyposis Registries increase in number. The risk of postsurgical extraintestinal complications is reason enough to urge life-long medical surveillance for all at-risk relatives.