Peutz-Jeghers syndrome: confirmation of linkage to chromosome 19p13.3 and identification of a potential second locus, on 19q13.4

Insights into targeting LKB1 in tumorigenesis

Genetic alterations to serine-threonine kinase 11 (STK11) have been implicated in Peutz-Jeghers syndrome and tumorigenesis. Further exploration of the context-specific roles of liver kinase B1 (LKB1; encoded by STK11) observed that it regulates AMP-activated protein kinase (AMPK) and AMPK-related kinases. Given that both migration and proliferation are enhanced with the loss of LKB1 activity combined with the prevalence of STK11 genetic alterations in cancer biopsies, LKB1 was marked as a tumor suppressor. However, the role of LKB1 in tumorigenesis is paradoxical as LKB1 activates autophagy and reactive oxygen species scavenging while dampening anoikis, which contribute to cancer cell survival. Due to the pro-tumorigenic properties of LKB1, targeting LKB1 pathways is now relevant for cancer treatment. With the recent successes of targeting LKB1 signaling in research and clinical settings, and enhanced cytotoxicity of chemical compounds in LKB1-deficient tumors, there is now a need for LKB1 inhibitors. However, validating LKB1 inhibitors is challenging as LKB1 adaptor proteins, nucleocytoplasmic shuttling, and splice variants all manipulate LKB1 activity. Furthermore, STE-20-related kinase adaptor protein (STRAD) and mouse protein 25 dictate LKB1 cellular localization and kinase activity. For these reasons, prior to assessing the efficacy and potency of pharmacological candidates, the functional status of LKB1 needs to be defined. Therefore, to improve the understanding of LKB1 in physiology and oncology, this review highlights the role of LKB1 in tumorigenesis and addresses the therapeutic relevancy of LKB1 inhibitors.

Progress report: Peutz-Jeghers syndrome

Peutz-Jeghers syndrome is a rare, autosomal dominant polyposis syndrome. Presenting with a remarkable phenotype including development of characteristic gastrointestinal polyps, mucocutaneous pigmentations, and an increased risk of cancer, the syndrome has been subject to many studies concerning the natural course of disease. In most patients, pathogenic germline variants are detected in the STK11 gene including cases of mosaicism and structural variants. Yet, studies assessing the effect of surveillance, understanding of cancer development, as well as clinical studies evaluating chemoprevention are lacking. In addition, the impact of Peutz-Jeghers syndrome on mental health, education, and family planning are insufficiently addressed. In this progress report, we describe current knowledge, clinical phenotype, surveillance strategies, and future areas of research.

Peutz-Jeghers syndrome: management for recurrent intussusceptions

BACKGROUND

Peutz-Jeghers syndrome (PJS) is an autosomal dominant disorder characterized by hamartomatous gastrointestinal polyps along with the characteristic mucocutaneous freckling. Multiple surgeries for recurrent intussusception in these children may lead to short bowel syndrome. Here we present our experience of management in such patients.

METHODS

From January 2015 to December 2023, we reviewed children of PJS, presented with recurrent intussusceptions. Data were collected regarding presentation, management, and follow-up with attention on management dilemma. Diagnosis of PJS was based on criteria laid by World Health Organization (WHO).

RESULTS

A total of nine patients were presented with age ranging from 4 to 17 years (median 9 years). A total of eighteen laparotomies were performed (7 outside, 11 at our centre). Among 11 laparotomies done at our centre, resection and anastomosis of bowel was done 3 times while 8 times enterotomy and polypectomy was done after reduction of intussusception. Upper and lower gastrointestinal endoscopy (UGIE & LGIE) was done in all cases while intraoperative enteroscopy (IOE) performed when required. Follow-up ranged from 2 months to 7 years.

CONCLUSION

Children with PJS have a high risk of multiple laparotomies due to polyps' complications. Considering the diffuse involvement of the gut, early decision of surgery and extensive bowel resection should not be done. Conservative treatment must be tried under close observation whenever there is surgical dilemma. The treatment should be directed in the form of limited resection or polypectomy after reduction of intussusception.

Peutz-Jeghers Syndrome: A Comprehensive Review of Genetics, Clinical Features, and Management Approaches

A relatively rare inherited condition known as Peutz-Jeghers syndrome (PJS) causes mucocutaneous pigmentation and gastrointestinal hamartomatous polyps. These polyps are non-cancerous, but the presence of PJS significantly increases the chances of developing various types of cancers, such as colorectal, pancreatic, gastric, and breast cancer. The purpose of this review article is to give an abbreviated summary of what is currently known about this syndrome, covering its clinical symptoms, pathophysiology, genetics, and management. PJS also raises the risk of getting many malignancies, especially gastrointestinal and pelvic cancers. Symptoms of the gastrointestinal tract brought on by hamartomatous polyps are frequent and include stool blockage, bleeding, and stomach pain. The pigmentation commonly appears as prominent bluish-black macules and frequently affects the skin and mucous membranes. Small macules and large regions of lentiginous pigmentation are both possible. Numerous areas, including the perioral area, buccal mucosa, fingers, and lips, exhibit pigmentation. Bowel obstruction and intussusception risk can be decreased by early identification and routine surveillance of gastrointestinal polyps. The gene serine/threonine kinase 11 (STK11) controls several biological functions, including cell polarity, growth, and proliferation. Genetic counseling is recommended for the affected individuals and their families. This can help assess the risk of passing on the condition to future generations and provide information about available reproductive options. Regular surveillance is crucial for managing the syndrome and reducing the risk of cancer development. Other syndromes and extra-gastrointestinal characteristics, such as somatic tumor polyps outside the gastrointestinal tract, are also linked to this syndrome.

[Management of the Peutz-Jeghers Syndrome]

The current evidence to guide management of Peutz-Jeghers Syndrome (PJS) is sparse. Here we summarise the European guidelines that were published in 2021 by the EHTG (European Hereditary Tumour Group), extended with new evidence on some aspects of clinical management that have been generated since then. EHTG with this revised guideline has updated and extended their own previous expert opinion guideline from 2010. For this purpose, all published literature was systematically screened and the level of evidence determined by using the GRADE methodology (Grading of Recommendations Assessment. Development and Evaluation). This was followed by a Delphi process and the consensus for a statement was achieved if the voting committee reached ≥ 80% approval.The only other more recently published guidelines encountered only addressed the clinical management of gastrointestinal and pancreatic manifestations of PJS. These recommendations were reviewed and adopted, since no further relevant literature was identified in the systematic literature search. However, additional questions were identified and formulated into recommendations after following the described process. It may be stated that 10 years after the predecessor guideline, new evidence has been sparse. As with all rare diseases, a call for more collaborative studies must here be made in order to improve patient management by addressing open clinical questions and generating collaborative evidence with increased case numbers, both nationally and internationally. With the limited published evidence, these European guidelines are the most current reference for management of PJS patients.

Clinical Efficacy of 755 nm Laser Treatment of Lip Mucosal Pigmentation in Children with Peutz–Jeghers Syndrome

Peutz–Jeghers syndrome (PJS) is a rare genetic disorder characterized by multiple gastrointestinal polyps and mucocutaneous pigmentation. Abnormal pigmentation typically develops in infancy or childhood. As PJS-related facial pigmentation can lead to psychological burden due to its effects on esthetics, treatment is required. Herein, we report on the efficacy and safety of treatment of lip mucosal pigmentation using a Q-switched 755 nm Alexandrite Laser in children with PJS, aged 2–12 years of age. A topical anesthetic was used prior to the application of laser therapy. A treatment efficacy of 100% was achieved with one to three treatments, with an excellent outcome achieved in five cases (62.5%) and a good outcome in three (37.5%). Recurrent pigmentation was observed in one case over the 6-month follow-up period. There were no adverse effects, such as scarring or hyperpigmentation or hypopigmentation. The treatment did cause pain, apprehension, and crying in some children, requiring special attention. Although our sample size is small, our findings do provide support of the high efficacy and safety of the Q-switched 755 nm Alexandrite Laser for the treatment of lip mucosal pigmentation in children with PJS. Further studies are required to confirm these findings.

The Management of Peutz-Jeghers Syndrome: European Hereditary Tumour Group (EHTG) Guideline

The scientific data to guide the management of Peutz–Jeghers syndrome (PJS) are sparse. The available evidence has been reviewed and discussed by diverse medical specialists in the field of PJS to update the previous guideline from 2010 and formulate a revised practical guideline for colleagues managing PJS patients. Methods: Literature searches were performed using MEDLINE, Embase, and Cochrane. Evidence levels and recommendation strengths were assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE). A Delphi process was followed, with consensus being reached when ≥80% of the voting guideline committee members agreed. Recommendations and statements: The only recent guidelines available were for gastrointestinal and pancreatic management. These were reviewed and endorsed after confirming that no more recent relevant papers had been published. Literature searches were performed for additional questions and yielded a variable number of relevant papers depending on the subject addressed. Additional recommendations and statements were formulated. Conclusions: A decade on, the evidence base for recommendations remains poor, and collaborative studies are required to provide better data about this rare condition. Within these restrictions, multisystem, clinical management recommendations for PJS have been formulated.

Beyond LKB1 Mutations in Non-Small Cell Lung Cancer: Defining LKB1less Phenotype to Optimize Patient Selection and Treatment

LKB1 is frequently mutated in non-small cell lung cancer (NSCLC). LKB1-mutated NSCLCs often have a dismal prognosis and receive lower benefit from the currently available therapies. LKB1 acts as a cell emergency brake in low-energy conditions, by modulating the activity of crucial anabolic enzymes. Thus, loss of LKB1 activity leads to the enhancement of tumor cell proliferation also under conditions of energy shortage. This unrestrained growth may be exploited as an Achilles heel in NSCLC, i.e., by inhibiting mitochondrial respiration. Recently, clinical trials have started to investigate the efficacy of metabolism-based treatments in NSCLCs. To date, enrollment of patients within these trials is based on LKB1 loss of function status, defined by mutation in the gene or by complete absence of immunohistochemical staining. However, LKB1 impairment could be the consequence of epigenetic regulations that partially or completely abrogate protein expression. These epigenetic regulations result in LKB1 wild-type tumors with aggressiveness and vulnerabilities similar to those of LKB1-mutated ones. In this review, we introduced the definition of the “LKB1less phenotype”, and we summarized all currently known features linked to this status, in order to optimize selection and treatment of NSCLC patients with impaired LKB1 function.

Novel germline STK11 variants and breast cancer phenotype identified in an Indian cohort of Peutz-Jeghers syndrome

Peutz-Jeghers syndrome (PJS) caused by germline STK11 variants is a rare autosomal dominant cancer predisposition syndrome characterized by multiple gastrointestinal (GI) hamartomatous polyps, mucocutaneous pigmentation and a high inherited risk of developing GI, breast and other cancers. Despite GI and breast being the two most common PJS-associated cancer sites, the immunohistochemical (IHC) and molecular features of these tumors in carriers of STK11 variant is not known. Detailed phenotyping including tumor IHC and its correlation with comprehensive STK11 genotyping by full gene sequencing followed by large genomic rearrangement analysis was performed in an Indian PJS cohort. A total of 4 distinct STK11 pathogenic or likely pathogenic variants were identified in 10 PJS cases from 7 of the 19 families tested-in 4/5 classical PJS families and 3/14 suspected PJS families. The pathogenic STK11 variant identified was novel in 3/7 families. In addition, four distinct, likely benign variants identified in seven families were also novel. All of the four breast cancer cases in families with STK11 pathogenic variant were estrogen receptor (ER)-positive and Her2-negative. Several novel STK11 variants identified in this Indian PJS cohort highlight the need to study PJS in different populations across the world. This is the first report showing ER positivity in breast cancer in carriers of STK11 variants and needs confirmation in a larger pooled cohort of PJS associated breast cancers. This could help establish the role of chemoprevention or prophylactic oophorectomy in female carriers of STK11 pathogenic variants.

Malignant tumors associated with Peutz-Jeghers syndrome: Five cases from a single surgical unit

BACKGROUND

Peutz-Jeghers syndrome (PJS) is an autosomal dominant inherited disease easily causing secondary malignant changes without effective treatments.

AIM

To assess the clinical characteristics, diagnosis, and treatment of malignant changes secondary to PJS.

METHODS

The clinical data of five patients with malignant changes secondary to PJS diagnosed and treated at Beijing Friendship Hospital from June 2014 to January 2017 were retrospectively analyzed; the follow-up ended in May 2018.

RESULTS

There were three male and two female patients with an average age of 43.6 years. Intestinal obstruction, intussusception, and abdominal pain were the first symptoms. Computed tomography and gastrointestinal imaging combined with endoscopy helped evaluate the depth of tumor infiltration and determine the need for radical resection. Three patients underwent surgery. Postoperative pathology confirmed adenocarcinoma, genetic test indicated STK11 mutation, and the patients received chemotherapy, including one who succumbed to tumor progression 6 months post-surgery. Other two patients underwent endoscopic resection, and postoperative pathology confirmed high grade intraepithelial neoplasia. The surviving patients had no recurrence by May 2018.

CONCLUSION

Endoscopy combined with computed tomography and gastrointestinal imaging is of great significance in the diagnosis and treatment of PJS, and pathological examination and gene detection are the gold standards for detecting malignant changes secondary to PJS. Some malignant polyps can be removed under endoscopy, and surgery is feasible when malignant polyps cannot be removed under an endoscope. For patients unable to achieve R0 resection, clinical symptoms should be relieved, and postoperative adjuvant chemotherapy could improve long-term prognosis. Meanwhile, close and regular surveillance should be conducted to prevent severe complications.

Sporadic Peutz-Jeghers syndrome: a rare cause of intussusception in a toddler with no medical history

Peutz–Jeghers syndrome (PJS) is an unusual hamartomatous polyposis of the gastrointestinal tract associated with melanocytic mucocutaneous hyperpigmentation. This research paper examines the case of an 18-month-old Syrian female who had been diagnosed with intussusception. The patient underwent laparotomy, and multiple small bowel polyps were found to act as the lead point. For this reason, small bowel resection (~15 cm), with end-to-end anastomosis, were performed. Although PJS diagnosis was histopathologically confirmed, the patient had no pigmented lesions on the face, the lower lip or the buccal mucosa and neither had any history of hospitalization or family history of the disease. This case was examined and is reported in the present study because PJS is rarely present at this early age when significant medical history is lacking.

Pathogenesis, diagnosis, and treatment of Peutz-Jeghers syndrome

Peutz-Jeghers syndrome (PJS), an autosomal dominant inherited disease, is caused by germinal mutations of the STK11. It is characterized by gastrointestinal hamartomas, mucocutaneous pigmentation and increased cancer risk. Germline mutations in STK11 cause a harmful effect on cell apoptosis, G1 arrest, and cell polarization, which leads to polyp formation and cancer occurrence. Balloon-assisted enteroscopy is widely used in removal of PJS polyps in the small bowel and it is proved to be safe and effective. We suggest to screen polyps and cancer in PJS patients, which seems to benefit these patients in the long run.

LKB1 as a Tumor Suppressor in Uterine Cancer: Mouse Models and Translational Studies

The LKB1 tumor suppressor was identified in 1998 as the gene mutated in the Peutz-Jeghers Syndrome (PJS), a hereditary cancer predisposition characterized by gastrointestinal polyposis and a high incidence of cancers, particularly carcinomas, at a variety of anatomic sites including the gastrointestinal tract, lung, and female reproductive tract. Women with PJS have a high incidence of carcinomas of the uterine corpus (endometrium) and cervix. The LKB1 gene is also somatically mutated in human cancers arising at these sites. Work in mouse models has highlighted the potency of LKB1 as an endometrial tumor suppressor and its distinctive roles in driving invasive and metastatic growth. These in vivo models represent tractable experimental systems for the discovery of underlying biological principles and molecular processes regulated by LKB1 in the context of tumorigenesis and also serve as useful preclinical model systems for experimental therapeutics. Here we review LKB1's known roles in mTOR signaling, metabolism, and cell polarity, with an emphasis on human pathology and mouse models relevant to uterine carcinogenesis, including cancers of the uterine corpus and cervix.

Correlation between genotype and phenotype in three families with Peutz-Jeghers Syndrome

Peutz-Jeghers syndrome (PJS) is a hereditary disorder characterized by mucocutaneous pigmentations, gastrointestinal (GI) polyposis and an increased risk of certain malignancies. Little is known about the causative genes of PJS, or their association with the clinical phenotypes of PJS. The present study reports the results of clinical and genetic analysis of three Chinese families with PJS. In addition, the medical histories and clinical manifestations of these families were compared. DNA was collected from the blood samples of patients with PJS and controls. Serine/threonine kinase 11 (STK11), olfactory receptor family 4 subfamily C member 45 (OR4C45) and zonadhesin (ZAN) were amplified by polymerase chain reaction, and analyzed by sequencing and cloning. Two PJS-affected members of one family had a de novo single base deletion (NM_000455.4:c.842delC) in the STK11 gene, and their clinical presentations reflected the quantity of mutant STK11 copies in a dose-dependent manner. No pathogenic variants of OR4C45 or ZAN were found in the patients with PJS, although a new single nucleotide polymorphism (NM_003386.2:c.5768delG) of ZAN was identified. The results of the current study identified that a STK11 mutation dose-dependent genotype-phenotype relationship exists in patients with PJS. In addition, an early onset and high severity of oral pigmentations in PJS was indicative of serious GI phenotypes. These findings may aid the diagnosis and treatment of PJS.

Peutz-Jeghers Syndrome: Pathobiology, Pathologic Manifestations, and Suggestions for Recommending Genetic Testing in Pathology Reports

Peutz-Jeghers syndrome (PJS), in most cases, is attributed to mutation in STK11/LKB1 and is clinically characterized by gastrointestinal hamartomatous polyposis, mucocutaneous pigmentation, and predisposition to certain neoplasms. There are currently no recommended gynecologic screening or clinical surveillance guidelines beyond those recommended for the general population; however, cervical cytology samples must be examined with a high level of suspicion for cervical adenocarcinoma. It is considered prudent to note the established association with PJS and recommend referral for genetic counseling. Complete surgical excision after a diagnosis of atypical lobular endocervical glandular hyperplasia is recommended.

[Rare hereditary syndromes associated with polyposis and the development of malignant tumors]

Familial adenomatous polyposis (FAP) and Peutz-Jeghers syndrome are genetic diseases characterized by gastrointestinal polyps, extraintestinal manifestations, and autosomal dominant inheritance. The carriers of these diseases from early childhood are at risk for neoplasias at different sites, which are symptomatic at various ages.

AIM

to study the clinical organ-specific manifestations in patients with FAP and Peutz-Jeghers, genetics update and possibilities of diagnosis, monitoring, and treatment of these diseases.

MATERIAL AND METHODS

The authors give the results of their examination and follow-up of children with FAP and Peutz-Jeghers hamartoma-polypous syndrome. In addition, current data from PubMed, Medline (including reviews, original articles and case reports) were used.

RESULTS

The main clinical organ-specific signs of multiple tumors in FAP and Peutz-Jeghers syndrome are shown. Data on the assessment of a risk for malignant tumors at various sites in the affected patients and their family members at different ages are provided. Each of these syndromes has a dissimilar genetic foundation. FAP is caused by the germline mutations in the APC gene, Peutz-Jeghers syndrome is by the STK11 gene, which predispose individuals to specifically associated neoplasias and require different follow-up strategies. Information on a phenotype-genotype correlation may serve as a reference point for the possible severity and various manifestations of a disease. An update on the molecular pathogenesis of these diseases is considered.

CONCLUSION

Molecular genetic testing of the genes associated with FAP and Peutz-Jeghers syndromes makes it possible to timely recognize family members at high risk, to plan therapeutic strategy and to affect the course of a disease. The joint participation of pediatricians, proctologists, oncologists, morphologists, geneticists, and molecular biologists is essential to timely recognize the carriers of the syndromes and a better prognosis in these patients.

Single-Nucleotide Polymorphism to Associate Cancer Risk

Genetic heterogeneity explains variation in predisposition for cancer. Whole-genome analysis allows risk to be quantified, giving better targeted screening and quantification of the personalized risk posed by environmental factors. Array-based approaches to whole-genome analysis are rapidly being overtaken by next-generation sequencing (NGS). In this review the different platforms currently available for NGS are compared and the opportunities and risks of this approach are discussed: including the informatics packages required and the ethical issues. Methods applicable to the personal genome machine (PGM) are given as an example of workflows.

Genodermatoses

Genodermatoses are an inherited disorder, present with multisystem involvement. Help us to identify regular mutations and appalling skin diseases with recessive inheritance. Genetic heterogeneity is very common, and molecular diagnosis requires a broad effort. Recurrent mutations in unrelated families were seen in families with xeroderma, Griscelli. It seems likely that eventually oligonucleotide arrays will replace most other methods for routine mutation scanning of the more common diseases and planned sequencing will be increasingly used for rarer diseases.

[Hereditary predisposition to cancers of the digestive tract, breast, gynecological and gonadal: focus on the Peutz-Jeghers]

Peutz-Jeghers syndrome (PJS) is a rare autosomal dominant disease due to mutations in the tumor suppressor gene STK11. PJS is characterized by periorificial hyperpigmented macules (lentiginosis) and hamartomatous polyposis. Polyps can be located anywhere in the gastrointestinal tract, but are preferably observed in the small bowel (70-90%), the colon (50%) and the stomach (25%). They tend to be cancerous in a particular sequence hamartoma-dysplasia-cancer. The diagnosis is often made in the first or second decade following the appearance of lentigines or upon the occurrence of complications due to polyps (obstruction, intussusception, occult bleeding responsible for anemia). Furthermore PJS is associated with a significant increase in cancer risk (relative risk of 89% over the life according to the most recent series). Digestive cancers are the more frequent with cumulative incidences of 55% for gastro-intestinal cancer (39% for colorectal cancer, 13% for small bowel cancer and between 11 and 36% for pancreatic cancer, respectively). There is also an increased risk of non digestive cancers. In particular the risk of breast cancer is similar to that of patients carrying deleterious BRCA1 or BRCA2 mutations (cumulative incidence of 45%). Gynecological and gonadal tumors are frequent as well and can be more (adenoma malignum) or less aggressive (ovarian sex cord tumors with annular tubules and testicular tumors with calcified Sertoli cells). Finally the frequency of lung cancer is moderately increased. Recommendations for screening and management based on retrospective series in the literature have led to various strategies. The aim of this paper is to summarize the clinical and molecular diagnostic criteria of PJS as well as recommendations on screening strategies, management and monitoring.

Exome sequencing revealed novel germline mutations in Chinese Peutz-Jeghers syndrome patients

BACKGROUND AND AIMS

Peutz-Jeghers Syndrome (PJS) is an autosomal dominant disorder which predisposes to the development of various cancers. Germline mutation in the serine/threonine kinase 11 gene (STK11) is known as one of the major causes of PJS. However, a notable proportion of PJS samples do not carry any mutation in STK11, suggesting possible genetic heterogeneity in the disease and the existence of other causative variants.

METHODS AND RESULTS

In order to identify other germline variants in the coding regions of the genome that are associated with PJS, we performed exome sequencing in three Chinese individuals with PJS and identified 16 common germline variants (12 protein-coding including STK11, 4 in pre-microRNAs). We further validated protein-coding variants in six PJS individuals (three with wild-type STK11) and predicted the functional impact. As result, we found that 7 coding variants are likely to have functional impacts. Especially, we identified 2 new germline variants which are represented in all six PJS samples and are independent of STK11 mutation.

CONCLUSIONS

Our study provided an exomic view of PJS. The germline variants identified in our analysis may help to resolve the complex genetic background of the disease and thus lead to the discovery of novel causative variants of PJS.

Protein expression and gene mutation of Brg1 in Peutz-Jeghers syndrome

AIM: To investigate the protein expression and gene mutation of Brahma-related gene 1 (Brg1) in Peutz-Jeghers syndrome (PJS), and to analyze their relation with tumor development.

METHODS: The expression of Brg1 protein in 72 cases of PJS polyps was detected by immunohistochemistry. Mutations in exons 4 and 10 of the Brg1 gene was detected by means of polymerase chain reaction-direct sequencing (PCR-DNA) in 39 cases of PJS polyps and 2 cases of carcinoma.

RESULTS: The positive rate of Brg1 protein expression in PJS (54.17%) was lower than that in adenocarcinoma (76.67%) but higher than that in normal tissue (16.67%). There was a significant difference in the positive rate of Brg1 protein expression among the three groups (P < 0.05). No Brg1 gene mutations were detected in 39 cases of PJS polyps and 2 cases of carcinoma.

CONCLUSION: Increased expression of Brg1 protein in PJS may be associated with the development of this disease. Brg1 gene mutations might be rare in PJS. Brg1 expression can be used as an important parameter for differentiating malignancy and evaluating prognosis of PJS.

Large deletions and splicing-site mutations in the STK11 gene in Peutz-Jeghers Chilean families

Peutz-Jeghers syndrome (PJS) is an autosomal dominant disorder characterized by mucocutaneous melanocytic macules, gastrointestinal hamartomatous polyposis and an increased risk of various neoplasms. Germline mutations in the serine/threonine kinase 11 (STK11) gene have been identified as a cause for PJS. The aim of this study was to characterize the genotype of Chilean PJS patients. Mutation screening of 13 patients from eight PJS families was performed using a single strand conformation polymorphism analysis, DNA sequencing and multiplex ligation-dependent probe amplification assay. The breakpoints of the genomic rearrangements were assessed by a long-range polymerase chain reaction and sequencing. The results revealed the existence of seven different pathogenic mutations in STK11 gene in seven unrelated families, including three point mutations and four large genomic deletions. Three of these point mutations (43%, 3/7) may be considered as novel. Our results showed that a germline mutation is present in STK11 in 88% of probands fulfilling the diagnostic criteria of PJS. In this study, the combination of two different experimental approaches in the screening of the STK11 in PJS, led to a higher percentage of mutation detection.

[Coexistence of Peutz-Jeghers' syndrome and Lynch's syndrome in the same patient]

Peutz-Jeghers' syndrome is an uncommon polyposis syndrome characterized by the presence of hamartomatous polyps in the gastrointestinal tract and mucocutaneous pigmentation (especially in the oral-nasal and perianal areas and hands and feet). Inheritance is autosomal dominant, caused by a germline mutation in the STK11 (LKB1) gene. The risk of breast and gastrointestinal cancer is increased in this syndrome. Lynch's syndrome is also known as hereditary non-polyposis colorectal cancer. This syndrome is caused by a mutation in DNA mismatch repair genes and increases the risk of colon and endometrial cancer, as well as that of other neoplasms (ovary, upper urological tract, gastric, small intestine, pancreas, skin and brain). We present the case of a young woman with colorectal cancer and the coexistence of both syndromes. This association has not previously been reported in the literature.

[Peutz-Jeghers syndrome, about 3 cases in siblings]

Le SPJ est une maladie rare de transmission autosomique dominante, défini par l’association d’une atteinte cutanée à type de lentiginose péri-orificielle d’une atteinte digestive, pulmonaire et des organes reproducteurs. Le gène de PJS a été localisé sur le chromosome 19p13.13. Les signes cutanés sont affichants et constituent un signe révélateur de la maladie, ils sont à type de lentigines, Ils siègent le plus souvent sur les lèvres, la muqueuse buccale. Les polypes digestifs constituent le deuxième signe cardinal de ce syndrome et ils peuvent révéler la maladie lorsqu’ils se manifestent d’emblée par leur complication telles les hémorragies digestives et les obstructions. Les personnes atteintes de SPJ courent un risque accru de cancers, le risque cumulatif de cancer est estimé à 93%, Les organes les plus fréquemment touchés sont le tractus gastro-intestinal (oesophage, estomac, intestin grêle, côlon, rectum et pancréas), le poumon, la prostate, le sein et les organes reproducteurs.

La prise en charge des SPJ est basée principalement sur la surveillance et le traitement des polypes hamartomateux. Il n′existe aucun traitement standarisé pour la pigmentation cutanéo-muqueuse. Le traitement fait appel à la cryochirurgie, la dermabrasion et au laser Q-switched.

Expression of Brg1, VEGF and COX-2 in Peutz-Jeghers syndrome

AIM: To detect the expression of brahma-related gene 1 (Brg1), vascular endothelial growth factor (VEGF) and cyclooxygenase 2 (COX-2) proteins in Peutz-Jeghers syndrome (PJS) and to analyze their clinical significance.

METHODS: Immunohistochemistry was used to detect the expression of Brg1, VEGF and COX-2 proteins in 72 PJS samples, 12 normal small intestinal mucosal tissue samples and 30 cancer tissue samples.

RESULTS: The positive rates of Brg1, VEGF and COX-2 expression were significantly higher in PJS than in normal mucosal tissue (54.17% vs 16.67%, 58.33% vs 8.33%, 62.50% vs 25.00%, all P < 0.01) and in cancer tissue than in PJS (76.67% vs 54.17%, 80.00% vs 58.33%, 83.33% vs 62.50% all P < 0.01). In PJS, positive correlations were found between Brg1 and VEGF expression and between Brg1 and COX-2 expression.

CONCLUSION: Brg1, VEGF and COX-2 may play a role in the occurrence of PJS.

Clinical genetics of hereditary colorectal cancer

Colorectal cancer (CRC) is a common disease, and approximately 25% of patients have a familial component. High-penetrance singlegene germline mutations conferring a true hereditary susceptibility account for around 5% to 6% of all cases. Lynch syndrome is the most common hereditary form of colorectal cancer. Much of the hereditary component in the remaining familial cases of CRC is likely polygenic, and many of the genetic changes involved are as yet unidentified. This article addresses the most clinically important CRC genetic syndromes.

Medical management update: Peutz Jeghers syndrome

Peutz Jeghers syndrome (PJS) is an autosomal dominant disease characterized by hamartomatous polyposis and distinct mucocutaneous pigmentation. PJS is associated with an increased risk for several cancers and other complications such as small intestine intussusception, short bowel syndrome, and anemia. Medical management mainly consists of treatment of the polyps and surveillance. This medical management update will review clinical concepts, therapeutic advances, and emphasize features of PJS important to the oral health care provider.

Hereditary hamartomatous polyposis syndromes: understanding the disease risks as children reach adulthood

Hamartomatous polyposis syndromes are a rare group of hereditary autosomal dominant disorders that comprise less than 1% of all hereditary colorectal cancers. Hamartomatous polyps, in and of themselves, are benign entities; however, these hamartomatous polyposis syndromes have a malignant potential for the development of colorectal cancer as well as extracolonic cancers. Early detection and proper surveillance are vital to minimizing the risk of carcinoma. This article provides a critical review of the clinical presentation, pathology, genetics, and screening and surveillance guidelines of juvenile polyposis syndrome, PTEN hamartoma tumor syndrome, and Peutz-Jeghers syndrome.

Single-nucleotide polymorphism (SNP) analysis to associate cancer risk

Identification of hereditary factors that predispose to cancer allows targeted cancer screening and better quantification of environmental risk factors. The ability to identify which single nucleotide polymorphisms (SNPs) are associated with cancer or segregate with disease in families allows high-risk loci to be identified. In this chapter, two platforms for analysing SNPs are discussed, the Affymetrix and Illumina systems. Application of both platforms requires the same principles of good laboratory practice but there are important differences in materials and methods, which will be discussed.

A case of Peutz-Jeghers syndrome with breast cancer, bilateral sex cord tumor with annular tubules, and adenoma malignum caused by STK11 gene mutation

BACKGROUND

Peutz-Jeghers syndrome (PJS) is a rare autosomal dominant disorder, and women with this syndrome are at an increased risk of developing intestinal and extraintestinal malignancies including breast and gynecologic malignancies. This case report presents a patient with PJS with a concomitant breast cancer, bilateral stromal tumors with annular tubules of the ovaries, and adenoma malignum of the cervix.

CASE

A 43-year-old woman presented with an advanced-stage breast cancer and a pelvic mass. The patient was treated with neoadjuvant chemotherapy followed by laparotomy with a hysterectomy and oophorectomy. Final pathologic examination revealed a concomitant breast cancer with metastasis to the ovaries, bilateral stromal tumors with annular tubules of the ovaries, and adenoma malignum of the cervix.

CONCLUSIONS

Patients with PJS are at a high risk for intestinal and extraintestinal malignancies and can present with multiple concomitant malignancies.

Mutations in STK11 gene in Czech Peutz-Jeghers patients

Background

Peutz-Jeghers syndrome (PJS) is an autosomal dominant hereditary disease characterized by mucocutaneous pigmentation and gastrointestinal hamartomatous polyposis. The germline mutations in the serine/threonine kinase 11 (STK11) gene have been shown to be associated with the disease. Individuals with PJS are at increased risk for development of various neoplasms. The aim of the present study was to characterize the genotype and phenotype of Czech patients with PJS.

Methods

We examined genomic DNA of 8 individuals from five Czech families by sequencing analysis of STK11 gene, covering its promotor region, the entire coding region and the splice-site boundaries, and by multiplex ligation-dependent probe amplification (MLPA) assay designed for the identification of large exonic deletions or duplications of STK11 gene.

Results

We found pathogenic mutations in STK11 gene in two families fulfilling the diagnostic criteria of PJS and in one of three sporadic cases not complying with the criteria. The patient with the frameshift mutation in STK11 gene developed aggressive gastric cancer. No other studied proband has developed a carcinoma so far.

Conclusion

Our results showed that a germline mutation of STK11 gene can be found not only in probands fulfilling the PJS diagnostic criteria, but also in some sporadic cases not complying with the criteria. Moreover, we observed a new case of aggressive gastric cancer in a young patient with a frameshift mutation of STK11 gene.

Hamartomatous polyposis syndromes

Since the histologic description of the hamartomatous polyp in 1957 by Horrilleno and colleagues, descriptions have appeared of several different syndromes with the propensity to develop these polyps in the upper and lower gastrointestinal tracts. These syndromes include juvenile polyposis, Peutz-Jeghers syndrome, hereditary mixed polyposis syndrome, and the phosphatase and tensin homolog gene (PTEN) hamartoma tumor syndromes (Cowden and Bannayan-Riley-Ruvalcaba syndromes), which are autosomal-dominantly inherited, and Cronkhite-Canada syndrome, which is acquired. This article reviews the clinical aspects, the molecular pathogenesis, the affected organ systems, the risks of cancer, and the management of these hamartomatous polyposis syndromes. Although the incidence of these syndromes is low, it is important for clinicians to recognize these disorders to prevent morbidity and mortality in these patients, and to perform presymptomatic testing in patients at risk.

Hepatic mesenchymal hamartoma: cytogenetic analysis of a case and review of the literature

Hepatic mesenchymal hamartoma (HMH) is a rare benign liver tumor generally occurring in young children. Abnormalities of chromosome 19q13.4 and chromosomal aneuploidy detected by flow cytometry have been reported in HMH. We recently analyzed a HMH in a 14-month-old girl and identified additional novel chromosome abnormalities, including hypodiploidy with deletions of several chromosomes, without rearrangement of 19q13.4 on both routine chromosome analysis and fluorescent in-situ hybridization analysis using subtelomere probes for chromosome 19q. This case underscores the need for chromosome analysis of all HMH and the need to report these changes to better understand the pathophysiology and the entire spectrum of cytogenetics of this uncommon tumor.

A novel de novo mutation in the serine-threonine kinase STK11 gene in a Korean patient with Peutz-Jeghers syndrome

Background

Peutz-Jeghers syndrome (PJS) is an unusual autosomal dominant disorder characterized by mucocutaneous pigmentation and multiple gastrointestinal hamartomatous polyps. Patients with PJS are at an increased risk of developing multi-organ cancer, most frequently those involving the gastrointestinal tract. Germline mutation of the STK11 gene, which encodes a serine-threonine kinase, is responsible for PJS.

Methods

Using DNA samples obtained from the patient and his family members, we sequenced nine exons and flanking intron regions of the STK11 gene using polymerase chain reaction (PCR) and direct sequencing.

Results

Sequencing of the STK11 gene in the proband of the family revealed a novel 1-base pair deletion of guanine (G) in exon 6 (c.826delG; Gly276AlafsX11). This mutation resulted in a premature termination at codon 286, predicting a partial loss of the kinase domain and complete loss of the C-terminal domain. We did not observe this mutation in both parents of the PJS patient. Therefore, it is considered a novel de novo mutation.

Conclusion

The results presented herein enlarge the spectrum of mutations of the STK11 gene by identifying a novel de novo mutation in a PJS patient and further support the hypothesis that STK11 mutations are disease-causing mutations for PJS with or without a positive family history.

Genetic defects underlying Peutz-Jeghers syndrome (PJS) and exclusion of the polarity-associated MARK/Par1 gene family as potential PJS candidates

LKB1/STK11 germline inactivations are identified in the majority (66-94%) of Peutz-Jeghers syndrome (PJS) patients. Therefore, defects in other genes or so far unidentified ways of LKB1 inactivation may cause PJS. The genes encoding the MARK proteins, homologues of the Par1 polarity protein that associates with Par4/Lkb1, were analyzed in this study because of their link to LKB1 and cell polarity. The genetic defect underlying PJS was determined through analysis of both LKB1 and all four MARK genes. LKB1 point mutations and small deletions were identified in 18 of 23 PJS families using direct sequencing and multiplex ligation-dependent probe amplification analysis identified exon deletions in 3 of 23 families. In total, 91% of the studied families showed LKB1 inactivation. Furthermore, a MARK1, MARK2, MARK3 and MARK4 mutation analysis and an MARK4 quantitative multiplex polymerase chain reaction analysis to identify exon deletions on another eight PJS families without identified LKB1 germline mutation did not identify mutations in the MARK genes. LKB1 defects are the major cause of PJS and genes of the MARK family do not represent alternative PJS genes. Other mechanisms of inactivation of LKB1 may cause PJS in the remaining families.

Molecular and clinical characteristics in 46 families affected with Peutz-Jeghers syndrome

Germline mutations of the tumor suppressor gene LKB1/STK11 are responsible for the Peutz-Jeghers syndrome (PJS), an autosomal-dominant disorder characterized by mucocutaneous pigmentation, hamartomatous polyps, and an increased risk of associated malignancies. In this study, we assessed the presence of pathogenic mutations in the LKB1/STK11 gene in 46 unrelated PJS families, and also carried genotype-phenotype correlation in regard of the development of cancer in 170 PJS patients belonging to these families. All LKB1/STK11 variants detected with single-strand conformational polymorphism were confirmed by direct sequencing, and those without LKB1/STK11 mutation were further submitted to Southern blot analysis for detection of deletions/rearrangements. Statistical analysis for genotype-phenotype correlation was performed. In 59% (27/46) of unrelated PJS cases, pathogenic mutations in the LKB1/STK11 gene, including 9 novel mutations, were identified. The new mutations were 2 splice site deletion-insertions, 2 missenses, 1 nonsense, and 4 abnormal splice sites. Genotype-phenotype analysis did not yield any significant differences between patients carrying mutations in LKB1/STK11 versus those without mutations, even with respect to primary biliary adenocarcinoma. This study presents the molecular characterization and cancer occurrence of a large cohort of PJS patients, increases the mutational spectrum of LKB1/STK11 allelic variants worldwide, and provides a new insight useful for clinical diagnosis and genetic counseling of PJS families.

[Family study in Peutz-Jeghers syndrome]

BACKGROUND

Peutz-Jeghers syndrome (PJS) is a rare autosomal dominant hereditary disease characterized by mucocutaneous pigmentation, gastrointestinal hamartomatous polyposis and an increased risk for the development of gastrointestinal and extra-gastrointestinal malignancies.

AIM AND METHODS

Five generations of two PJS families (21-21 patients) were analyzed to summarize the clinical appearance of the disorder by interview, physical examination, laboratory and imaging studies.

RESULTS

Phenotypic variability was observed in PJS both in and between families. In family "A" 13 people were diagnosed as being affected, all of them had melanin spots at birth and the first presenting clinical symptom was colicky abdominal pain (median age 12 years, range: 2-35) resulting in 14 laparotomies in 9 of the affected persons. 4/13 patients died from small-bowel ileus (median age 7 years, range 2-31), 2/13 from GI cancer (median age 54 years). In family "B" 7 patients were documented as being affected. The first features were also abdominal cramps (at age 22). The main causes of death were gynaecological (1/5) and GI malignancies (4/5) at advanced age, no one died in ileus.

CONCLUSIONS

The results based on the analysis of the two families suggest that PJS is not a benign disease. It is difficult to predict the outcome of the disorder regarding the variable expression and incomplete penetrance. Therefore we emphasize the importance of checking the pedigree, finding out the leading symptom in the family; hemoccult test and routine lab studies should be carried out at every affected individual. If clinical signs and symptoms are present we recommend to perform the complete diagnostic protocol and a yearly follow-up by a gastroenterologist familiar with PJS focusing on the leading symptoms.

STK11 status and intussusception risk in Peutz-Jeghers syndrome

BACKGROUND

Peutz-Jeghers syndrome (PJS) is caused by germline STK11 mutations and characterised by gastrointestinal polyposis. Although small bowel intussusception is a recognised complication of PJS, risk varies between patients.

OBJECTIVE

To analyse the time to onset of intussusception in a large series of PJS probands.

METHODS

STK11 mutation status was evaluated in 225 PJS probands and medical histories of the patients reviewed.

RESULTS

135 (60%) of the probands possessed a germline STK11 mutation; 109 (48%) probands had a history of intussusception at a median age of 15.0 years but with wide variability (range 3.7 to 45.4 years). Median time to onset of intussusception was not significantly different between those with identified mutations and those with no mutation detected, at 14.7 years and 16.4 years, respectively (log-rank test of difference, chi(2) = 0.58, with 1df; p = 0.45). Similarly no differences were observed between patient groups on the basis of the type or site of STK11 mutation.

CONCLUSIONS

The risk of intussusception in PJS is not influenced by STK11 mutation status.

A novel mutation in STK11 gene is associated with Peutz-Jeghers Syndrome in Indian patients

BACKGROUND

Peutz-Jeghers syndrome (PJS) is a rare multi-organ cancer syndrome and understanding its genetic basis may help comprehend the molecular mechanism of familial cancer. A number of germ line mutations in the STK11 gene, encoding a serine threonine kinase have been reported in these patients. However, STK11 mutations do not explain all PJS cases. An earlier study reported absence of STK11 mutations in two Indian families and suggested another potential locus on 19q13.4 in one of them.

METHODS

We sequenced the promoter and the coding region including the splice-site junctions of the STK11 gene in 16 affected members from ten well-characterized Indian PJS families with a positive family history.

RESULTS

We did not observe any of the reported mutations in the STK11 gene in the index patients from these families. We identified a novel pathogenic mutation (c.790_793 delTTTG) in the STK11 gene in one index patient (10%) and three members of his family. The mutation resulted in a frame-shift leading to premature termination of the STK11 protein at 286th codon, disruption of kinase domain and complete loss of C-terminal regulatory domain. Based on these results, we could offer predictive genetic testing, prenatal diagnosis and genetic counselling to other members of the family.

CONCLUSION

Ours is the first study reporting the presence of STK11 mutation in Indian PJS patients. It also suggests that reported mutations in the STK11 gene are not responsible for the disease and novel mutations also do not account for many Indian PJS patients. Large-scale genomic deletions in the STK11 gene or another locus may be associated with the PJS phenotype in India and are worth future investigation.

Frequency and spectrum of cancers in the Peutz-Jeghers syndrome

BACKGROUND

Although an increased cancer risk in Peutz-Jeghers syndrome is established, data on the spectrum of tumors associated with the disease and the influence of germ-line STK11/LKB1 (serine/threonine kinase) mutation status are limited.

EXPERIMENTAL DESIGN

We analyzed the incidence of cancer in 419 individuals with Peutz-Jeghers syndrome, and 297 had documented STK11/LKB1 mutations.

RESULTS

Ninety-six cancers were found among individuals with Peutz-Jeghers syndrome. The risk for developing cancer at ages 20, 30, 40, 50, 60, and 70 years was 2%, 5%, 17%, 31%, 60%, and 85%, respectively. The most common cancers represented in this analysis were gastrointestinal in origin, gastroesophageal, small bowel, colorectal, and pancreatic, and the risk for these cancers at ages 30, 40, 50, and 60 years was 1%, 9%, 15%, and 33%, respectively. In women with Peutz-Jeghers syndrome, the risk of breast cancer was substantially increased, being 8% and 31% at ages 40 and 60 years, respectively. Kaplan-Meier analysis showed that cancer risks were similar in Peutz-Jeghers syndrome patients with identified STK11/LKB1 mutations and those with no detectable mutation (log-rank test of difference chi2 = 0.62; 1 df; P = 0.43). Furthermore, the type or site of STK11/LKB1 mutation did not significantly influence cancer risk.

CONCLUSIONS

The results from our study provide quantitative information on the spectrum of cancers and risks of specific cancer types associated with Peutz-Jeghers syndrome.

Cancer risks in LKB1 germline mutation carriers

BACKGROUND AND AIMS

Germline mutations in the LKB1 gene are known to cause Peutz-Jeghers syndrome, which is an autosomal dominant disorder characterised by hamartomatous polyposis and mucocutaneous pigmentation. This syndrome is associated with an increased risk of malignancies in different organs but there is a lack of data on cancer range and risk in LKB1 germline mutation carriers.

PATIENTS AND METHODS

The cumulative incidence of cancer in 149 Peutz-Jeghers syndrome patients with germline mutation(s) in LKB1 was estimated using Kaplan-Meier time to cancer onset analyses and compared between relevant subgroups with log rank tests.

RESULTS

Thirty two cancers were found in LKB1 mutation carriers. Overall cancer risks at ages 30, 40, 50, 60, and 70 years were 6%, 18%, 31%, 41%, and 67%, respectively. There were similar overall cancer risks between male and female carriers. However, there were overall cancer risk differences for exon 6 mutation carriers versus non-exon 6 mutation carriers (log rank p=0.022 overall, 0.56 in males, 0.0000084 in females). Most (22/32) of the cancers occurred in the gastrointestinal tract, and the overall gastrointestinal cancer risks at ages 40, 50, 60, and 70 years were 12%, 24%, 34%, and 63%, respectively. In females, the risks for developing gynaecologic cancer at ages 40 and 50 years were 13% and 18%, respectively.

CONCLUSIONS

Mutations in exon 6 of LKB1 are associated with a higher cancer risk than mutations within other regions of the gene. Moreover, this study provides age related cumulative risks of developing cancer in LKB1 mutation carriers that should be useful for developing a tailor made cancer surveillance protocol for Peutz-Jeghers syndrome patients.

Exonic STK11 deletions are not a rare cause of Peutz-Jeghers syndrome

BACKGROUND

Peutz-Jeghers syndrome (PJS) is a rare, autosomal dominant cancer predisposition syndrome characterised by oro-facial pigmentation and hamartomatous polyposis of the gastrointestinal tract. A causal germline mutation in STK11 can be identified in 30% to 80% of PJS patients.

METHODS

Here we report the comprehensive mutational analysis of STK11 in 38 PJS probands applying conventional PCR based mutation detection methods and the recently introduced MLPA (multiplex ligation dependent probe amplification) technique developed for the identification of exonic deletions/duplications.

RESULTS

Nineteen of 38 probands (50%) had detectable point mutations or small scale deletions/insertions and six probands (16%) had genomic deletions encompassing one or more STK11 exons.

CONCLUSIONS

These findings demonstrate that exonic STK11 deletions are a common cause of PJS and provide a strong rationale for conducting a primary screen for such mutations in patients.

An unexpected Cowden syndrome case found among members of a large familial adenomatous polyposis kindred

Genetic testing is now considered the standard of care in the management of familial adenomatous polyposis (FAP). Non-carriers of mutations are excluded from endoscopic surveillance. During the systematic screening of the relatives of an affected member with FAP, one non-carrier of APC mutations was unexpectedly found with the typical Cowden syndrome phenotype. One large Algerian family with FAP was screened for an APC germline mutation. Moreover, we also performed a mutation search in the Cowden syndrome member for PTEN, BMPR1A or MADH4 (SMAD4) germline mutations. We identified a mutation in the APC gene that results in a truncated protein (Y935X) in the FAP proband, and subsequently in 12 FAP-affected members. Among the 12 APC mutation-negative members of this family, we found one member with the Cowden disease phenotype. However, the mutation analysis in the PTEN gene and the two other genes involved in juvenile polyposis, namely BMPR1A and MADH4 (SMAD4), in the Cowden syndrome patient failed to show any pathogenic mutation. Genetic testing is a powerful tool that can provide a definitive diagnosis for FAP. However, not all polyposes in the FAP family are adenomatous polyposes.