An exploration of genotype-phenotype link between Peutz-Jeghers syndrome and STK11: a review

Somatic STK11 mosaicism in a Turkish patient with Peutz-Jeghers syndrome

Peutz-Jeghers syndrome (PJS) is an autosomal dominant disorder, caused by germline variants in the serine/threonine kinase 11 (STK11) gene. However, mosaic variants in STK11 gene have been rarely described. A 25-year-old woman diagnosed with PJS due to multiple hamartomatous polyps in the gastrointestinal tract was referred to our clinic. In the molecular diagnosis, the patient was evaluated using the STK11 gene sequence analysis and multiplex ligation-dependent probe amplification (MLPA) method, which suggested no pathogenic variant to account for the clinical picture. Given that the clinical findings of the patient were consistent with those of PJS, the raw data from next-generation sequencing (NGS) were re-examined for mosaicism which led to the detection of a novel mosaic c.920 + 1G > T variant in STK11 gene with a rate of 23% (1860x). Deep read-level NGS was performed on buccal mucosa and polyp samples to determine mosaicism levels in other tissues. Variant frequencies were 29% (710x) and 31% (1301x), respectively. Mosaicism should be considered in cases with clear clinical diagnostic criteria, such as PJS, where the pathogenic variant cannot be detected by sequence analysis and MLPA methods. Identification of mosaicism in these patients is very important as it can have an impact on patient follow-up and genetic counseling for relatives.

Age-specific causes of upper gastrointestinal bleeding in children

The etiology of upper gastrointestinal bleeding (UGIB) varies by age, from newborns to adolescents, with some of the causes overlapping between age groups. While particular causes such as vitamin K deficiency and cow's milk protein allergy are limited to specific age groups, occurring only in neonates and infants, others such as erosive esophagitis and gastritis may be identified at all ages. Furthermore, the incidence of UGIB is variable throughout the world and in different hospital settings. In North America and Europe, most UGIBs are non-variceal, associated with erosive esophagitis, gastritis, and gastric and duodenal ulcers. In recent years, the most common causes in some Middle Eastern and Far Eastern countries are becoming similar to those in Western countries. However, variceal bleeding still predominates in certain parts of the world, especially in South Asia. The most severe hemorrhage arises from variceal bleeding, peptic ulceration, and disseminated intravascular coagulation. Hematemesis is a credible indicator of a UGI source of bleeding in the majority of patients. Being familiar with the most likely UGIB causes in specific ages and geographic areas is especially important for adequate orientation in clinical settings, the use of proper diagnostic tests, and rapid initiation of the therapy. The fundamental approach to the management of UGIB includes an immediate assessment of severity, detecting possible causes, and providing hemodynamic stability, followed by early endoscopy. Unusual UGIB causes must always be considered when establishing a diagnosis in the pediatric population because some of them are unique to children. Endoscopic techniques are of significant diagnostic value, and combined with medicaments, may be used for the management of acute bleeding. Finally, surgical treatment is reserved for the most severe bleeding.

A one-stop approach to diagnosing hereditary colorectal cancer in the Chinese population

BACKGROUND AND AIM

The current procedure for identifying hereditary colorectal cancer (HCRC) is time consuming in clinical practice. This study aimed to develop a time-saving approach to diagnosing HCRC.

METHODS

A total of 100 suspected HCRC patients were prospectively enrolled (cohort 1) and 116 colorectal cancer patients with DNA mismatch repair-deficient were retrospectively included (cohort 2). Next-generation sequencing (NGS) tests were performed on tumors and matched white blood cells (WBCs) or normal tissues. Using the conventional method upon WBC/normal tissue-based NGS data as a reference, the performance of the ColonCore method using tumor-only-based NGS data in predicting germline variants was explored in cohort 1 and validated in cohort 2.

RESULTS

In cohort 1, the ColonCore method diagnosed 17 Lynch syndrome (LS) and 14 familial adenomatous polyposis (FAP); and by the conventional method, the cases were 16 and 10, respectively. The ColonCore method showed sensitivities of 100% in diagnosing LS (positive predictive value [PPV] 94.1%) and FAP (PPV 71.4%). Moreover, two of seven patients with multiple adenomas/polyps who did not meet existing clinical criteria for HCRC were predicted to harbor germline variants in APC and MUTYH. Additionally, the sensitivity of the ColonCore method in identifying LS patients from cohort 2 reached 85.7% with a PPV of 85.7%.

CONCLUSION

The ColonCore method might be an acceptable tool for predicting germline variants associated with HCRC. Our work indicates the essentiality of NGS tests in CRC patients for precision diagnosis and treatment.

Small Intestinal Polyp Burden in Pediatric Peutz-Jeghers Syndrome Assessed through Capsule Endoscopy: A Longitudinal Study

The management of pediatric Peutz-Jeghers Syndrome (PJS) focuses on the prevention of intussusception complicating small intestinal (SI) polyposis. This hinges on the accurate appraisal of the polyp burden to tailor therapeutic interventions. Video Capsule Endoscopy (VCE) is an established tool to study SI polyps in children, but an in-depth characterization of polyp burden in this population is lacking. Methods: We performed a retrospective longitudinal cross-sectional analysis of VCE studies in pediatric PJS patients at our institution (CMKC) from 2010 to 2020. Demographic, clinical, and VCE findings reported by three reviewers in tandem were accrued. Polyp burden variables were modeled as functions of patient and study characteristics using linear mixed models adjusted for clustering. Results: The cohort included 15 patients. The total small bowel polyp count and largest polyp size clustered under 30 polyps and <20 mm in size. Luminal occlusion correlated closely with the estimated polyp size. Polyp distribution favored proximal (77%) over distal (66%) small bowel involvement. The adjusted largest polyp size was greater in males. Double Balloon Enteroscopy was associated with a decreased polyp burden. Conclusions: The polyp burden in pediatric PJS patients favors the proximal third of the small intestine, with relatively small numbers and a polyp size amenable to resection through enteroscopy. Male gender and older age were related to an increased polyp burden.

Cancer Predisposition Syndromes and Thyroid Cancer: Keys for a Short Two-Way Street

Cancer predisposition syndromes are entities determined especially by germinal pathogenic variants, with most of them autosomal dominantly inherited. The risk of a form of cancer is variable throughout life and affects various organs, including the thyroid. Knowing the heterogeneous clinical picture and the existing genotype-phenotype correlations in some forms of thyroid cancer associated with these syndromes is important for adequate and early management of patients and families. This review synthesizes the current knowledge on genes and proteins involved in cancer predisposition syndromes with thyroid cancer and the phenomena of heterogeneity (locus, allelic, mutational, and clinical).

Peutz-Jeghers syndrome without STK11 mutation may correlate with less severe clinical manifestations in Chinese patients

BACKGROUND

Peutz-Jeghers syndrome (PJS) is an autosomal dominant genetic disease with skin mucosal pigment spots and gastrointestinal (GI) multiple hamartoma polyps as clinical characteristics. At present, it is considered that the germline mutation of STK11 gene is the genetic cause of PJS. However, not all PJS patients can be detected STK11 germline mutations. The specific clinical characteristics of these PJS patients without STK11 mutation is an interesting clinical question. Or, like wild type GI stromal tumor, whether these PJS without STK11 mutation are also called PJS is worth discussing. Therefore, we designed the study to understand the clinical characteristics of these PJS patients without STK11 mutation.

AIM

To investigates whether PJS patients with known STK11 mutations have a more severe spectrum of clinical phenotypes compared to those without.

METHODS

A total of 92 patients with PJS admitted to the Air Force Medical Center from 2010 to 2022 were randomly selected for study. Genomic DNA samples were extracted from peripheral blood samples, and pathogenic germline mutations of STK11 were detected by high-throughput next-generation gene sequencing. Clinical-pathologic manifestations of patients with and without STK11/LKB1 mutations were compared.

RESULTS

STK11 germline mutations were observed in 73 patients with PJS. Among 19 patients with no detectable STK11 mutations, six had no pathogenic germline mutations of other genes, while 13 had other genetic mutations. Compared with PJS patients with STK11 mutations, those without tended to be older at the age of initial treatment, age of first intussusception and age of initial surgery. They also had a lower number of total hospitalizations relating to intussusception or intestinal obstruction, and a lower load of small intestine polyps.

CONCLUSION

PJS patients without STK11 mutations might have less severe clinical-pathologic manifestations than those with.

Hereditary cancer syndromes

Hereditary cancer syndromes (HCSs) are arguably the most frequent category of Mendelian genetic diseases, as at least 2% of presumably healthy subjects carry highly-penetrant tumor-predisposing pathogenic variants (PVs). Hereditary breast-ovarian cancer and Lynch syndrome make the highest contribution to cancer morbidity; in addition, there are several dozen less frequent types of familial tumors. The development of the majority albeit not all hereditary malignancies involves two-hit mechanism, i.e. the somatic inactivation of the remaining copy of the affected gene. Earlier studies on cancer families suggested nearly fatal penetrance for the majority of HCS genes; however, population-based investigations and especially large-scale next-generation sequencing data sets demonstrate that the presence of some highly-penetrant PVs is often compatible with healthy status. Hereditary cancer research initially focused mainly on cancer detection and prevention. Recent studies identified multiple HCS-specific drug vulnerabilities, which translated into the development of highly efficient therapeutic options.

A novel missense mutation of the STK11 gene in a Chinese family with Peutz-Jeghers syndrome

BACKGROUND

Peutz-Jeghers syndrome (PJS) is a rare autosomal dominant inherited disease caused by mutations in the Serine-Threonine Kinase 11 (STK11) gene. This study aimed to diagnose a Chinese pedigree with PJS and to expand the spectrum of STK11 variants.

METHODS

We performed an inductive analysis of clinical features, gastrointestinal endoscopy, radiologic imaging, and pathological findings in a Chinese family with PJS. Whole-exome sequencing (WES), Sanger sequencing, and STK11 protein 3D structure prediction were performed for establishing a molecular diagnosis.

RESULTS

The proband, her mother, and grandfather presented with pigmentation spots on lips, oral mucosa, and fingers. Her mother and grandfather also had pigmentation spots on face and feet, while her brother had pigmentation spots only on the lower lip. On endoscopy, polyps were discovered in the proband, her mother, and grandfather. A novel heterozygous mutation (c.521A > C) in exon 4 of STK11 was identified in all four patients, leading to a change from histidine to proline in amino acid 174. The variable site p.H174 was highly conserved in different species on multiple sequence alignment analysis.

CONCLUSIONS

We diagnosed a Chinese pedigree with PJS based on clinical features, gastrointestinal endoscopy, and genetic testing results. Our results expanded the spectrum of STK11 variants, which will be helpful for genetic counseling.

Unexpected Widespread Bone Metastases from a BRAF K601N Mutated Follicular Thyroid Carcinoma within a Previously Resected Multinodular Goiter

Follicular thyroid carcinoma (FTC) represents the second most common malignant thyroid neoplasm after papillary carcinoma (PTC). FTC is characterized by the tendency to metastasize to distant sites such as bone and lung. In the last 20 years, the understanding of the molecular pathology of thyroid tumors has greatly improved. Uncommon BRAF non-V600E mutations have been identified and are generally believed to associate with follicular patterned tumors of low malignant potential, particularly non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTPs) (i.e., non-invasive encapsulated follicular variant PTC). We here report for the first time widespread bone metastases from a BRAF K601N mutated follicular tumor.

Altered Gut Microbiota in Patients With Peutz–Jeghers Syndrome

Background

Peutz–Jeghers syndrome (PJS) is a rare genetic disorder characterized by the development of pigmented spots and gastrointestinal polyps and increased susceptibility to cancers. It remains unknown whether gut microbiota dysbiosis is linked to PJS.

Aim

This study aimed to assess the structure and composition of the gut microbiota, including both bacteria and fungi, in patients with PJS and investigate the relationship between gut microbiota dysbiosis and PJS pathogenesis.

Methods

The bacterial and fungal composition of the fecal microbiota was analyzed in 23 patients with PJS (cases), 17 first-degree asymptomatic relatives (ARs), and 24 healthy controls (HCs) using 16S (MiSeq) and ITS2 (pyrosequencing) sequencing for bacteria and fungi, respectively. Differential analyses of the intestinal flora were performed from the phylum to species level.

Results

Alpha-diversity distributions of bacteria and fungi indicated that the abundance of both taxa differed between PJS cases and controls. However, while the diversity and composition of fecal bacteria in PJS cases were significantly different from those in ARs and HCs, fungal flora was more stable. High-throughput sequencing confirmed the special characteristics and biodiversity of the fecal bacterial and fungal microflora in patients with PJS. They had lower bacterial biodiversity than controls, with a higher frequency of the Proteobacteria phylum, Enterobacteriaceae family, and Escherichia-Shigella genus, and a lower frequency of the Firmicutes phylum and the Lachnospiraceae and Ruminococcaceae families. Of fungi, Candida was significantly higher in PJS cases than in controls.

Conclusion

The findings reported here confirm gut microbiota dysbiosis in patients with PJS. This is the first report on the bacterial and fungal microbiota profile of subjects with PJS, which may be meaningful to provide a structural basis for further research on intestinal microecology in PJS.

STK11 Prevents Invasion through Signal Transducer and Activator of Transcription 3/5 and FAK Repression in Cutaneous Melanoma

The STK11/LKB1 is a tumor suppressor involved in metabolism and cell motility. In BRAFV600E melanoma, STK11 is inactivated by extracellular signal‒regulated kinase and RSK, preventing it from binding and activating adenosine monophosphate-activated protein kinase and promoting melanoma cell proliferation. Although STK11 mutations occur in 5‒10% of cutaneous melanoma, few functional studies have been performed. By knocking out STK11 with CRISPR/Cas9 in two human BRAF-mutant melanoma cell lines, we found that STK11 loss reduced the sensitivity to a BRAF inhibitor. More strikingly, STK11 loss led to an increased invasive phenotype in both three-dimensional spheroids and in vivo zebrafish xenograft models. STK11 overexpression consistently reversed the invasive phenotype. Interestingly, STK11 knockout increased invasion also in an NRAS-mutant melanoma cell line. Furthermore, although STK11 was expressed in primary human melanoma tumors, its expression significantly decreased in melanoma metastases, especially in brain metastases. In the STK11-knockout cells, we observed increased activating phosphorylation of signal transducer and activator of transcription 3/5 and FAK. Using inhibitors of signal transducer and activator of transcription 3/5 and FAK, we reversed the invasive phenotype in both BRAF- and NRAS-mutated cells. Our findings confirm an increased invasive phenotype on STK11 inactivation in BRAF- and NRAS-mutant cutaneous melanoma that can be targeted by signal transducer and activator of transcription 3/5 and FAK inhibition.

Testicular Sertoli cell tumour and potentially testicular Leydig cell tumour are features of DICER1 syndrome

DICER1 syndrome is a rare paediatric autosomal dominant inherited disorder predisposing to various benign and malignant tumours. It is caused by a germline pathogenic variant in DICER1, and the second hit for tumour development is usually a missense hotspot pathogenic variant in the DICER1 ribonuclease IIIb domain. While DICER1 predisposing variants account for about 60% of ovarian Sertoli-Leydig cell tumours, no DICER1-related testicular stromal tumours have been described. Here we report the first two cases of testicular stromal tumours in children carrying a DICER1 germline pathogenic variant: a case of Sertoli cell tumour and a case of Leydig cell tumour diagnosed at 2 and 12 years of age, respectively. A somatic DICER1 hotspot pathogenic variant was detected in the Sertoli cell tumour. This report extends the spectrum of DICER1-related tumours to include testicular Sertoli cell tumour and potentially testicular Leydig cell tumour. Diagnosis of a testicular Sertoli cell tumour should prompt DICER1 genetic testing so that patients with a DICER1 germline pathogenic variant can benefit from established surveillance guidelines. DICER1 genetic evaluation may be considered for testicular Leydig cell tumour. Our findings suggest that miRNA dysregulation underlies the aetiology of some testicular stromal tumours.

Hereditary gynecologic tumors and precision cancer medicine

Gynecologic cancers are more often caused by genetic factors than other cancers. Genetic testing has become a promising avenue for the prevention, prognosis, and treatment of cancers. This review describes molecular features of gynecologic tumors linked to hereditary syndromes, gives an overview of the current state of clinical management, and clarifies the role of gynecology in the treatment of hereditary tumors. Typical hereditary gynecologic tumors include hereditary breast and ovarian cancer, Lynch syndrome, Peutz-Jeghers syndrome, and Cowden syndrome. Multigene panel testing, which analyzes a preselected subset of genes for genetic variants, has recently become the first-choice test because it can provide more accurate risk assessment than a single test. Furthermore, comprehensive genomic cancer profiling enables personalized cancer treatment and aids in germline findings.

Gastric-type mucinous adenocarcinoma of the cervix in a woman with Peutz-Jeghers syndrome: a case report

BACKGROUND

Peutz-Jeghers syndrome (PJS) is a rare autosomal dominant disorder characterized by a predisposition to the development of multiple neoplasms. Gastric-type mucinous adenocarcinoma (GAS), a new variant of carcinoma of the cervix according to 2014 WHO classification, is less common compared with squamous cell carcinoma, is more aggressive and has a lower 5-year survival rate compared with the usual-type endocervical adenocarcinoma, and is also unrelated to human papillomavirus (HPV) infection.

CASE SUMMARY

We herein present the case of a 32-year-old patient with PJS who was diagnosed with GAS of the cervix. The patient was not sexually active and had been diagnosed with PJS at 2 years of age. A tumor ∼6 cm was found on the cervix and was diagnosed as GAS of the cervix of clinical-stage IB3. The patient was treated with intra-arterial chemotherapy for one course, followed by radical surgery and then systematic chemotherapy.

CONCLUSION

The present case highlights the need for more thorough cancer screening for patients with PJS, as this disorder is rare and is associated with a high risk of malignancies. Young patients with PJS, including those who are not sexually active, who present with watery vaginal discharge or bleeding should be screened for cervical carcinoma, even if the cytological results or HPV tests are negative.

Risk for Surgery in Patients with Polyposis Syndrome after Therapy by Device-Assisted Enteroscopy (DAE): Long-Term Follow Up

Background and aim of the study: Polyposis syndromes such as Peutz–Jeghers (PJ) and familial adenomatous polyposis (FAP) are associated with the growth of small bowel polyps; the risk is approximately 60–90% for PJ and 40–70% for FAP. The primary aim of this study was to evaluate the efficacy of device-assisted enteroscopy (DAE) in the detection and treatment of small bowel polyps to reduce the risk of surgery. The secondary objective was to study complications and mortality. Methods: We conducted a retrospective cohort study by analyzing a structured database. Between September 2006 and October 2019, we observed and followed 42 consecutive patients with polyposis syndromes; they underwent device-assisted enteroscopy and three were excluded from elective surgery after the exam. The endoscopic exams were performed for diagnostic and therapeutic purposes. Results: Thirty-nine patients were evaluated with a mean follow up of 6.7 years (±SD 2.7), 79.5% were female with a mean age of 43.8 years (±SD 15.02), and 68 enteroscopies were performed with the removal of 64 polypoid lesions. One bleeding episode occurred after operative enteroscopy, and the need for subsequent surgery occurred in six patients with PJ and in five patients with FAP. The surgical indications in PJ patients were the presence of large polyps (three patients) and three cases of intussusception, one of which was a patient with a polyp in the proximal ileum, not reachable with the scope. One patient with PJ died from pancreatic cancer during follow up. The surgical indications in patients with FAP were the presence of four large polyps with high-grade dysplasia and one ampullary neoplasia recurrence. Conclusions: In PJ patients, the endoscopic treatment of small bowel polyps was safe. During the follow-up period, the patients with successful endoscopic treatment did not need surgery. In FAP patients treated with DAE, none developed cancer.

Genotypic and Phenotypic Characteristics of Hereditary Colorectal Cancer

The genomic causes and clinical manifestations of hereditary colorectal cancer (HCRC) might be stratified into 2 groups, namely, familial (FCRC) and a limited sense of HCRC, respectively. Otherwise, FCRC is canonically classified into 2 major categories; Lynch syndrome (LS) or associated spectra and inherited polyposis syndrome. By contrast, despite an increasing body of genotypic and phenotypic traits, some FCRC cannot be clearly differentiated as definitively single type, and the situation has become more complex as additional causative genes have been discovered. This review provides an overview of HCRC, including 6 LS or associated spectra and 8 inherited polyposis syndromes, according to molecular pathogenesis. Variants and newly-identified FCRC are particularly emphasized, including MUTYH (or MYH)-associated polyposis, Muir-Torre syndrome, constitutional mismatch repair deficiency, EPCAM-associated LS, polymerase proofreading-associated polyposis, RNF43- or NTHL1-associated serrated polyposis syndrome, PTEN hamartoma tumor syndrome, and hereditary mixed polyposis syndrome. We also comment on the clinical utility of multigene panel tests, focusing on comprehensive cancer panels that include HCRC. Finally, HCRC surveillance strategies are recommended, based on revised or notable concepts underpinned by competent validation and clinical implications, and favoring major guidelines. As hereditary syndromes are mainly attributable to genomic constitutions of distinctive ancestral groups, an integrative national HCRC registry and guideline is an urgent priority.

Solitary Peutz-Jeghers Type Polyp of Jejunum with Gastric Fundic and Antral Gland Lining Mucosa: A Case Report and Review of Literature

Solitary Peutz-Jeghers type polyps are characterized by a hamartomatous polyp of the gastrointestinal (GI) tract in a patient without mucocutaneous pigmentation, family history of Peutz-Jeghers syndrome, or STK11/LKB1 mutations. Histologically identical to the polyps in Peutz-Jeghers syndrome, these sporadic polyps can arise anywhere along the GI tract, with typical arborizing smooth muscles extending from the muscularis mucosa. While the lining mucosa is generally the same as the organ in which it arises, gastric pyloric and osseous metaplasia have been reported in intestinal polyps in Peutz-Jeghers syndrome. Herein, the authors report the first case of a small intestinal solitary Peutz-Jeghers type polyp with gastric antral and fundic gland lining mucosa. A 43-year-old male was admitted for small bowel obstruction. Diagnostic laparoscopy revealed jejuno-jejunal intussusception with an associated polyp measuring 7.2 cm. Histological examination showed a hamartomatous polyp with arborizing smooth muscle bundles extending from the muscularis mucosae. The polyp was lined by non-dysplastic gastric antral and fundic gland mucosa, and was sharply demarcated from the adjacent non-polypoid intestinal mucosa. Colonoscopy, esophagogastroduodenoscopy and small bowel enteroscopy revealed no additional polyps or masses. Thorough investigation of the patient's family history was negative for Peutz-Jeghers syndrome or mucocutaneous pigmentation. Molecular analysis of the lesion was negative for STK11/LKB1 mutations. A diagnosis of solitary Peutz-Jeghers type polyp of the small bowel with gastric antral and fundic gland mucosal lining was rendered.

A Review of Breast Cancer Risk Factors in Adolescents and Young Adults

Simple Summary

Cancer diagnosed in patients between the ages of 15 and 39 deserves special consideration. Diagnoses within this cohort of adolescents and young adults include childhood cancers which present at an older age than expected, or an early presentation of cancers that are typically observed in older adults, such as breast cancer. Cancers within this age group are associated with worse disease-free and overall survival rates, and the incidence of these cases are rising. Knowing an individual’s susceptibility to disease can change their clinical management and allow for the risk-testing of relatives. This review discusses the risk factors that contribute to breast cancer in this unique cohort of patients, including inherited genetic risk factors, as well as environmental and lifestyle factors. We also describe risk models that allow clinicians to quantify a patient’s lifetime risk of developing disease.

Abstract

Cancer in adolescents and young adults (AYAs) deserves special consideration for several reasons. AYA cancers encompass paediatric malignancies that present at an older age than expected, or early-onset of cancers that are typically observed in adults. However, disease diagnosed in the AYA population is distinct to those same cancers which are diagnosed in a paediatric or older adult setting. Worse disease-free and overall survival outcomes are observed in the AYA setting, and the incidence of AYA cancers is increasing. Knowledge of an individual’s underlying cancer predisposition can influence their clinical care and may facilitate early tumour surveillance strategies and cascade testing of at-risk relatives. This information can further influence reproductive decision making. In this review we discuss the risk factors contributing to AYA breast cancer, such as heritable predisposition, environmental, and lifestyle factors. We also describe a number of risk models which incorporate genetic factors that aid clinicians in quantifying an individual’s lifetime risk of disease.

Genetic Characterization of Hereditary Cancer Syndromes Based on Targeted Next-Generation Sequencing

A hereditary cancer syndrome is a genetic predisposition to cancer caused by a germline mutation in cancer-related genes. Identifying the disease-causing variant is important for both the patient and relatives at risk in cancer families because this could be a guide in treatment and secondary cancer prevention. In this study, hereditary cancer panel harboring cancer-related genes was performed on MiSeq Illumina NGS system from peripheral blood samples. Sequencing files were fed into a cloud-based data analysis pipeline. Reportable variants were classified according to the American College of Medical Genetics and Genomics guidelines. Three hundred five individuals were included in the study. Different pathogenic/likely pathogenic variants were detected in 75 individuals. The majority of these variants were in the <i>MUTYH</i>, <i>BRCA2</i>, and <i>CHEK2</i> genes. Nine novel pathogenic/likely pathogenic variants were identified in <i>BRCA1</i>, <i>BRCA2</i>, <i>GALNT12</i>, <i>ATM</i>, <i>MLH1</i>, <i>MSH2</i>, <i>APC</i>, and <i>KIT</i> genes. We obtained interesting and novel variants which could be related to hereditary cancer, and this study confirmed that NGS is an indispensable method for the risk assessment in cancer families.

Minimally Invasive Elective Surgery as a Treatment of Bowel Invagination in a Peutz-Jeghers Syndrome Case

We present a case of a 24-year-old woman with Peutz-Jeghers syndrome, recurrent colic abdominal pain, and lower gastrointestinal bleed for the last 5 years. Colonoscopy showed hamartomas without any dysplasia. In the enteral magnetic resonance imaging, a distal jejunum and ileum invagination, secondary to hamartomas was detected. The patient was referred to the Surgery Department and despite few symptoms, elective surgery was proposed. By laparoscopic surgery approach, the entire bowel was carefully revised, 3 intussusceptions and bowel volvulus were found, 2 in jejunum and 1 in ileum, causing incomplete obstruction and intestinal dilatation, with a diameter of 6 cm. These intussusception areas were marked with a silk filament, after achieving devolvulation and disinvagination. A 5-cm laparotomy was done, to externalize the entire bowel, to explore it manually, to verify the absence of other lesions, and locate silk points. By longitudinal enterotomies on the antimesenteric intestinal border where silk filaments were located, the polyps were removed through their stalk, and the enterotomies were transversely closed. Postoperative evolution was favorable, starting oral tolerance on the fourth day and being discharged from the hospital on the seventh day. Eight months later, the patient was asymptomatic with a better quality of life.

Appendiceal carcinoid in a pediatric patient with Peutz-Jeghers syndrome: A case report and comprehensive literature review

RATIONALE

Peutz-Jeghers syndrome (PJS), a rare autosomal dominant disorder, is characterized by mucocutaneous pigmentations, hamartomatous polyps in the gastrointestinal tract, and a high risk of developing various malignancies. To the best of our knowledge, only 1 case of appendiceal carcinoid associated with PJS has been previously reported in the pediatric population.

PATIENT CONCERNS

We report a 7-year-old girl who was admitted for severe, intermittent abdominal pain and cramps, nausea, and vomiting. Multiple brown melanotic macules on the lips, buccal mucosa, and the tongue were noted.

DIAGNOSIS

A plain abdominal X-ray in a standing position revealed dilated intestinal loops with multiple air-fluid levels. A computed tomography scan of the abdomen showing a "coffee bean" appearance of the jejunal loop with a transition point to the duodenal loop. Axial-contrast-enhanced computed tomography scan of the abdomen showing dilated jejunum loops, filled with fluid with the swirled appearance of mesentery typical for volvulus. The diagnosis of PJS was based on clinical findings along with the histopathologic confirmation of the hamartomatous polyps.

INTERVENTIONS

An emergency laparotomy was performed, revealing a jejunojejunal intussusception starting 40 cm from the duodenojejunal flexure. Jejunotomy revealed that a lead-point intussusception was a necrotic hamartomatous polyp. After resecting the involved jejunal necrotic segment, including the polyp, end-to-end jejuno-jejunal anastomosis was performed. Further exploration revealed the presence of a jejunal mass 80 cm from the duodenojejunal flexure identified as another hamartomatous pedunculated polyp. The polyp was resected, and the enterotomy was then closed transversely. The grossly normal appendix was also removed.

OUTCOMES

Clinical findings along with the histopathologically confirmed hamartomatous polyps were consistent with PJS. An appendiceal carcinoid (well-differentiated neuroendocrine tumor, European Neuroendocrine Tumor Society stage pT2) was incidentally detected during histological examination of the appendix. The patient and parents were counseled accordingly, focusing on active surveillance and control of symptoms. Two additional hamartomatous polyps (gastric and jejunal) were detected endoscopically and resected in the fourth postoperative week. A regular, 1-year follow-up and surveillance revealed no complications or recurrences.

LESSONS

Unusual neoplasms can occasionally be encountered in well-defined syndromes such as PJS. Therefore, active follow-up and surveillance are mandatory for all patients with PJS.

Gene of the month: STK11

STK11 encodes for the protein liver kinase B1, a serine/threonine kinase which is involved in a number of physiological processes including regulation of cellular metabolism, cell polarity and the DNA damage response. It acts as a tumour suppressor via multiple mechanisms, most classically through AMP-activated protein kinase-mediated inhibition of the mammalian target of rapamycin signalling pathway. Germline loss-of-function mutations in STK11 give rise to Peutz-Jeghers syndrome, which is associated with hamartomatous polyps of the gastrointestinal tract, mucocutaneous pigmentation and a substantially increased lifetime risk of many cancers. In the sporadic setting, STK11 mutations are commonly seen in a subset of adenocarcinomas of the lung in addition to a number of other tumours occurring at various sites. Mutations in STK11 have been associated with worse prognoses across a range of malignancies and may be a predictor of poor response to immunotherapy in a subset of lung cancers, though further studies are needed before the presence of STK11 mutations can be implemented as a routine clinical biomarker.

Peutz-Jeghers syndrome

PURPOSE OF REVIEW

Peutz-Jeghers syndrome is a rare, autosomal dominant, hereditary polyposis syndrome defined by gastrointestinal hamartomas and mucocutaneous pigmentations, caused by a germline mutation in the serine/ threonine kinase 11 or liver kinase B1 (STK11/LKB1) genes. Hamartomatous polyps located throughout the gastrointestinal tract can be complicated by bleeding and small bowel intussusception, potentially leading to the need for emergency surgery. Individuals suffering from Peutz-Jeghers syndrome have an increased lifetime risk of various forms of cancer (gastrointestinal, pancreatic, lung, breast, uterine, ovarian and testicular). Surveillance should lead to the prevention of complications and thus a reduction in mortality and morbidity of patients.

RECENT FINDINGS

A combined approach based on wireless capsule endoscopy, magnetic resonance enterography and device-assisted enteroscopy is effective in reduction of the polyp burden and thus decreasing the risk of bleeding and intussusception. Current guidelines for screening and surveillance are mostly based on expert opinion rather than evidence.

SUMMARY

Peutz-Jeghers syndrome is an emerging disease that significantly affects the quality of life enjoyed by patients. Despite of all the progress in improved early diagnostics, options for advanced endoscopic therapy and elaborate surveillance, acute and chronic complications decrease the life expectancy of patients suffering from Peutz-Jeghers syndrome.

BRCA and Breast Cancer-Related High-Penetrance Genes

Genetic susceptibility explains 5-10% of all breast cancer cases. High-penetrance breast cancer susceptibility genes deliberate a greater than tenfold relative risk of breast cancer. BRCA1 and BRCA2 genes are the most common cause of hereditary breast cancer, and TP53, PTEN, and SKT11 (LKB1) are rarely present. The prevalence of BRCA1 and BRCA2 genetic alterations differ in various ethnic groups. The Korean Hereditary Breast Cancer (KOHBRA) Study, nationwide-scale study, was established to acquire evidence for the accurate risk assessment and management of hereditary breast and ovarian cancer (HBOC) in Korea prospectively since 2007. In this chapter, we review previous research related to hereditary breast cancer and summarize the present concepts and research results centered on the Korean Hereditary Breast Cancer Research at this time.

Implications of Splicing Alterations in the Onset and Phenotypic Variability of a Family with Subclinical Manifestation of Peutz-Jeghers Syndrome: Bioinformatic and Molecular Evidence

Peutz–Jeghers Syndrome (PJS) is an autosomal dominant pre-cancerous disorder caused in 80–90% of cases by germline mutations in the tumor suppressor gene STK11. We performed a genetic test of the STK11 gene in two Italian young sisters suspected of PJS, since they showed pathognomonic café au lait spots in absence of other symptoms and familiarity. Sequencing of all exons of STK11 gene and other 8 genes, suggested to be involved in hamartomatous syndromes, (PTEN, BMPR1A, SDHB, SDHD, SMAD4, AKT1, ENG, PIK3CA) led to the identification in both the probands of a novel germline silent mutation named c.597 G>A, hitting the last nucleotide of exon 4. Interestingly, genetic testing of the two probands’ parents showed that their unaffected father was carrier of this mutation. Moreover, he carried a second intronic substitution named c.465-51 T>C (rs2075606) which was not inherited by his daughters. We also observed that all the family members carrying the c.597 G>A mutation presented an aberrant splice variant of STK11 mRNA lacking exon 4. Furthermore, in silico analysis of c.465-51 T>C substitution showed that it may activate an Enhancer Splicing Element. Finally, qRT-PCR analysis of STK11 expression levels showed a slight downregulation of the wild type allele in the father and a 2-fold downregulation in the probands compared to the unaffected mother. Our results have led the hypothesis that the c.465-51 T>C intronic variant, which segregates with the wild type allele, could increase the splicing effectiveness of STK11 wild-type allele and compensate the side effect of the c.597 G>A splicing mutation, being responsible for the phenotypic variability observed within this family. This finding highlight the importance of RNA analysis in genetic testing, remarking that silent DNA variant can often be splicing variant involved in disease onset and progression. The identification of these variants has a crucial role to ensure an appropriate follow-up and cancer prevention in at-risk individuals.

Mutation analysis of related genes in hamartoma polyp tissue of Peutz-Jeghers syndrome

BACKGROUND

Peutz-Jeghers syndrome (PJS) is a rare disease with clinical manifestations of pigmented spots on the lips, mucous membranes and extremities, scattered gastrointestinal polyps, and susceptibility to tumors. The clinical heterogeneity of PJS is obvious, and the relationship between clinical phenotype and genotype is still unclear.

AIM

To investigate the mutation status of hereditary colorectal tumor-associated genes in hamartoma polyp tissue of PJS patients and discuss its relationship with the clinicopathological data of PJS.

METHODS

Twenty patients with PJS were randomly selected for this study and were treated in the Air Force Medical Center (former Air Force General Hospital) PLA between 2008 and 2017. Their hamartoma polyp tissues were used for APC, AXIN2, BMPR1A, EPCAM, MLH1, MLH3, MSH2, MSH6, MUTYH, PMS1, PMS2, PTEN, SMAD4, and LKB1/STK11 gene sequencing using next-generation sequencing technology. The correlations between the sequencing results and clinical pathological data of PJS were analyzed.

RESULTS

Fourteen types of LKB1/STK11 mutations were detected in 16 cases (80.0%), of which 8 new mutations were found (3 types of frameshift deletion mutations: c.243delG, c.363_364delGA, and c.722delC; 2 types of frameshift insertions: c. 144_145insGCAAG, and c.454_455insC; 3 types of splice site mutations: c.464+1G>T, c.464+1G>A, and c.598-1G>A); 9 cases (45.0%) were found to have 18 types of heterozygous mutations in the remaining 13 genes except LKB1/STK11. Of these, MSH2: c.792+1G>A, MSH6: c.3689C>G, c.4001+13C>CTTAC, PMS1: c.46C>t, and c.922G>A were new mutations.

CONCLUSION

The genetic mutations in hamartoma polyp tissue of PJS are complex and diverse. Moreover, other gene mutations in PJS hamartoma polyp tissue were observed, with the exception of LKB1/STK11 gene, especially the DNA mismatch repair gene (MMR). Colorectal hamartoma polyps with LKB1/STK11 mutations were larger in diameter than those with other gene mutations.

Primary experience of small bowel polypectomy with balloon-assisted enteroscopy in young pediatric Peutz-Jeghers syndrome patients

For Peutz-Jeghers syndrome (PJS) patients, small bowel polyps develop and result in symptoms at an early age. Balloon-assisted enteroscopy (BAE) is verified as a safe and efficient choice to evaluate and remove small intestinal polyps in adult PJS. But the safety of BAE, especially BAE-facilitated polypectomy for young pediatrics, is little known. This prospective study focused on the effectiveness and safety of BAE-facilitated polypectomy in small bowel for young pediatric PJS. PJS patients (aged 0-14 years old) with BAE (including both single-balloon and double-balloon enteroscopies) were included from 1 September 2012 to 30 April 2018. The demographic data, medical history, and details of BAE were recorded. BAE-related complications and symptom relief after BAE were evaluated and compared between the PJS patients aged 5-10 years old (the younger pediatric group) and those aged 11-14 years old (the older pediatric group). A total of 41 pediatric PJS patients (5-14 years old) subjected to 82 BAEs were included. BAE-facilitated polypectomy was performed for 33 children (80.5%), and 242 polyps in small bowel were removed. For 10 (24.4%) patients, one or more giant polyps (maximum diameter larger than 5 cm) were removed. For eight patients, no polypectomy was done as no polyps were observed (six subjects) or not suitable for BAE-facilitated polypectomy (two subjects) because of high risk of perforation. The complication rates of BAE and BAE-facilitated polypectomy were 1.2% (1/82) and 1.8% (1/55), and the symptom relief rate was 70.8% (17/24). Compared with the older pediatric group, the younger pediatric group showed no increased BAE complication rate (0.0% vs. 5.0%, p = 0.488) and a comparable rate of symptom relief after BAE therapy (80.8% vs. 55.6%, p = 0.356).Conclusion: BAE-facilitated polypectomy in young pediatric PJS is safe and effective.What is known:• Small bowel evaluation and prophetic polypectomy are important for pediatric PJS patients to avoid polyp-related intussusception, obstruction, and bleeding.• BAE polypectomy was a recommended intervention for removing small bowel polyps in adult PJS patients.What is new:• BAE-facilitated small bowel polypectomy is safe and effective for young pediatric PJS, even for those aged less than 10 years old.

Birt-Hogg-Dubé syndrome with simultaneous hyperplastic polyposis of the gastrointestinal tract: case report and review of the literature

Background

Birt-Hogg-Dubé syndrome (BHDS) is a rare autosomal dominant genodermatosis characterized by benign growth of the hair follicles, the presence of pulmonary cysts, spontaneous pneumothorax, and bilateral renal tumors that are usually hybrid oncocytic or multifocal chromophobe renal cell carcinoma. The diagnosis is confirmed by the presence of a pathogenic variant in the tumor suppressor folliculin (FLCN) gene mapped at 17p11.2. Although the dermatological lesions typical of BHDS are benign and only cause aesthetic concerns, and the pulmonary manifestations are controllable, the greater tendency of patients with this syndrome to present benign or malignant renal tumors, often bilateral and multifocal, makes the diagnosis of this syndrome important for the prognosis of the patients. The objective was to report the case of a patient with BHDS, without pulmonary manifestations and with hyperplastic polyposis of the gastrointestinal tract, and to perform a literature review.

Case presentation

A 60-year-old man complained of abdominal pain and diarrhoea for 2 months. Physical examination was normal except for the presence of normochromic papules in the frontal region of the face associated with hyperkeratotic and hyperchromic papules in the dorsal region. The excisional biopsies of the skin lesions indicated trichodiscomas. Esophagogastroduodenoscopy, enteroscopy, and colonoscopy showed the presence of hyperplastic polyps in the stomach, duodenum, jejunum, colon, and rectum. Computed tomography (CT) and magnetic resonance imaging (MRI) of the abdomen revealed multiple expansive solid lesions in both kidneys, with necrotic and calcified areas. Renal magnetic resonance angiography also showed a solid lesion in the right kidney measuring 5 cm in diameter and another solid lesion in the left kidney measuring 8 cm in diameter, both suggestive of renal angiomyolipoma. CT scans of the skull, chest, and temporal bones were normal. The genetic study revealed the presence of a variant of FLCN in the intron 13.

Conclusions

To the best of our knowledge, this is the first reported case of BHDS with the simultaneous finding of gastrointestinal hyperplastic polyposis, which may represent a possible phenotypic expression of this syndrome that has not yet been described.

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.

Peutz-Jeghers syndrome with mesenteric fibromatosis: A case report and review of literature

BACKGROUND

Peutz-Jeghers syndrome (PJS) and mesenteric fibromatosis (MF) are rare diseases, and PJS accompanying MF has not been previously reported. Here, we report a case of a 36-year-old man with both PJS and MF, who underwent total colectomy and MF surgical excision without regular follow-up. Two years later, he sought treatment for recurrent acute abdominal pain. Emergency computed tomography showed multiple soft tissue masses in the abdominal and pelvic cavity, and adhesions in the small bowel and peritoneum. Partial intestinal resection and excision of the recurrent MF were performed to relieve the symptoms.

CASE SUMMARY

A 36-year-old male patient underwent total colectomy for PJS with MF. No regular reexamination was performed after the operation. Two years later, due to intestinal obstruction caused by MF enveloping part of the small intestine and peritoneum, the patient came to our hospital for treatment. Extensive recurrence was observed in the abdomen and pelvic cavity. The MF had invaded the small intestine and could not be relieved intraoperatively. Finally, partial bowel resection, proximal stoma, and intravenous nutrition were performed to maintain life.

CONCLUSION

Regular detection is the primary way to prevent deterioration from PJS. Although MF is a benign tumor, it has characteristics of invasive growth and ready recurrence. Therefore, close follow-up of both the history of MF and gastrointestinal surgery are advisable. Early detection and early treatment are the main means of improving patient prognosis.

Use of Family History and Genetic Testing to Determine Risk of Colorectal Cancer

Approximately 35% of patients with colorectal cancer (CRC) have a family history of the disease attributed to genetic factors, common exposures, or both. Some families with a history of CRC carry genetic variants that cause CRC with high or moderate penetrance, but these account for only 5% to 10% of CRC cases. Most families with a history of CRC and/or adenomas do not carry genetic variants associated with cancer syndromes; this is called common familial CRC. Our understanding of familial predisposition to CRC and cancer syndromes has increased rapidly due to advances in next-generation sequencing technologies. As a result, there has been a shift from genetic testing for specific inherited cancer syndromes based on clinical criteria alone, to simultaneous testing of multiple genes for cancer-associated variants. We summarize current knowledge of common familial CRC, provide an update on syndromes associated with CRC (including the nonpolyposis and polyposis types), and review current recommendations for CRC screening and surveillance. We also provide an approach to genetic evaluation and testing in clinical practice. Determination of CRC risk based on family cancer history and results of genetic testing can provide a personalized approach to cancer screening and prevention, with optimal use of colonoscopy to effectively decrease CRC incidence and mortality.

Long-Term Outcome in Patients with a Solitary Peutz-Jeghers Polyp

Background

Clinical characteristics and prognosis of patients with a solitary Peutz-Jeghers polyp (PJP) have not been fully investigated.

Methods

Solitary PJP was diagnosed when a single hamartomatous lesion was identified in the gastrointestinal tract of patients without mucocutaneous pigmentation or a family history of Peutz-Jeghers syndrome. We retrospectively reviewed 51 patients (32 men and 19 women) with a solitary PJP and analyzed the sex, age at diagnosis, endoscopic features, and outcomes in this patient group. The STK11/LKB1 germline mutation was not investigated in any of the patients.

Results

The mean age of the 51 patients was 66.1 years. The polyp was found in the duodenum (N = 10), jejunum (N = 2), cecum (N = 2), transverse colon (N = 5), sigmoid colon (N = 21), or rectum (N = 11). Most of the polyps presented as a pedunculated lesion (N = 40), followed by semipedunculated (N = 9) and sessile (N = 2) morphologies. The mean size of a solitary PJP was 15.6 mm (range: 5 to 33 mm). During a mean endoscopic follow-up period of 4.5 years (range: 0.1 to 16.1 years), no recurrence was identified. Eighteen of the enrolled patients had a history of cancer or concomitant cancer. Five patients died due to non-gastrointestinal-related causes. No additional cancer or death directly related to solitary PJP was observed.

Conclusions

Solitary PJPs did not recur in this study. Although examination of the entire gastrointestinal tract using esophagogastroduodenoscopy, enteroscopy, and colonoscopy is desirable to exclude Peutz-Jeghers syndrome, follow-up endoscopy after endoscopic polyp resection may be unnecessary, once the diagnosis of a solitary PJP is made.

[Pigmented macules as possible early signs of genetic syndromes]

Solitary congenital or early apparent pigmented macules are usually without relevance; however, when multiple, extensive or in a patterned arrangement, they are not uncommonly the first sign of an underlying genetic syndrome. The present article gives an overview on the clinical significance of multiple café-au-lait macules, multiple lentigines and pigmentary mosaicism and discusses the differential diagnosis of associated syndromes. Early diagnosis with the essential contribution of the dermatologist is not only important for genetic counseling but can also contribute to avoidance of sometimes life-threatening complications.

Somatic PRKAR1A Gene Mutation in a Nonsyndromic Metastatic Large Cell Calcifying Sertoli Cell Tumor

Large cell calcifying Sertoli cell tumors (LCCSCTs) are rare testicular tumors, representing <1% of all testicular neoplasms. Almost 40% of patients with LCCSCTs will present in the context of an inherited tumor predisposition condition, such as Carney complex (CNC) or Peutz-Jeghers syndrome. We report the case of a 42-year-old man who had presented with a right testicular mass, and was diagnosed with metastatic LCCSCT. The patient underwent radical orchiectomy, achieving initial remission of his disease. However, lymph node and hepatic metastases were identified. He received chemotherapy without response, and he died of complications of his disease 4 years after the initial diagnosis. Genetic analysis of the tumor and a lymph node metastasis identified a somatic frameshift mutation in the PRKAR1A gene (c.319delG, p.E107fs*22). The mutation was predicted to result in premature termination of the PRKAR1A protein and, thus, not be expressed at the protein level, consistent with other PRKAR1A nonsense mutations. The patient was extensively screened for signs of CNC, but he had no stigmata of the complex. To the best of our knowledge, the present report is the first of a somatic mutation in the PRKAR1A gene shown to be associated with a seemingly sporadic case of LCCSCT. Somatic PRKAR1A mutations are rare in sporadic tumors, and it is unknown whether this mutation was causative of LCCSCT in our patient who did not have CNC, or contributed to the malignancy of the tumor, which might have been caused by additional mutations.

Familial Pancreatic Cancer

Familial pancreatic cancer accounts for 10% of all patients with pancreatic cancer. Because the 5-year survival rate of pancreatic cancer is only 7%, screening programs for high-risk individuals are essential and might be advantageous. Pancreatic ductal adenocarcinoma mostly shows symptoms at an advanced state and treatment is not efficient enough to cure most patients. People with hereditary tumor syndromes or their affected relatives can also be included in such screening programs. Besides the collection of data to investigate the background of the disease, these screening programs aim to diagnose and treat precursor lesions so that more dangerous, invasive lesions are prevented. These precursor lesions can be pancreatic intraepithelial neoplasia, intraductal papillary mucinous neoplasm, and mucinous cystic neoplasm. This review summarizes the latest knowledge of pancreatic screening programs, shows the procedure of pancreatic cancer screening, and gives an overview of current guidelines.