Manifestations of juvenile polyposis syndrome in SMAD4 mutation carriers of a kindred

Occurrence of gastric cancer in patients with juvenile polyposis syndrome: a systematic review and meta-analysis

BACKGROUND AND AIMS

The true rate of gastric cancer (GC) in juvenile polyposis syndrome (JPS) is unknown because of its rarity and ascertainment bias in published literature. To better assess this, we conducted a systematic review and meta-analysis.

METHODS

MEDLINE, Embase, and Scopus databases were searched for the key words juvenile polyposis syndrome, juvenile polyps, stomach cancer, GC, SMAD4, BMPR1A, hamartomatous polyposis syndrome, hamartomas, and hereditary cancers for studies reporting upper GI manifestations in JPS. The primary outcome was the reported occurrence of GC in JPS. We then compared GC occurrence based on the presence or absence of pathogenic germline variants (PGVs) and in untested patients.

RESULTS

Eleven studies including 637 patients were included. The pooled occurrence of GC was 3.5% (95% confidence interval [CI], 1.8-5.2; I² = 12.3%) at a median age of 42.5 years (range, 15-57.6). The pooled occurrence of GC in patients with SMAD4 PGV was 10.1% (95% CI, 3.2-16.8%; I² = 54.7%). GC was reported in only 1 BMPR1A PGV carrier and was not reported in patients without an identifiable PGV. In patients with prior germline testing, the risk of GC was higher in SMAD4 PGV carriers (odds ratio, 11.6; 95% CI, 4.6-29.4; I² = 18.3%) compared with patients without SMAD4 PGV. In JPS patients with unknown status of germline testing, pooled occurrence of GC was 7.5% (95% CI, 0-15.5). There was an overall moderate risk of bias in the studies.

CONCLUSIONS

GC is highest in SMAD4-associated JPS and was not reported in patients without identifiable PGVs. The value of GC surveillance in BMPR1A PGV carriers and JPS patients without an identifiable PGV is questionable. Germline testing should be performed in all JPS patients to inform GC risk discussion and utility of surveillance.

Transforming growth factor-β in liver cancer stem cells and regeneration

Cancer stem cells have established mechanisms that contribute to tumor heterogeneity as well as resistance to therapy. Over 40% of hepatocellular carcinomas (HCCs) are considered to be clonal and arise from a stem-like/cancer stem cell. Moreover, HCC is the second leading cause of cancer death worldwide, and an improved understanding of cancer stem cells and targeting these in this cancer are urgently needed. Multiple studies have revealed etiological patterns and multiple genes/pathways signifying initiation and progression of HCC; however, unlike the transforming growth factor β (TGF-β) pathway, loss of p53 and/or activation of β-catenin do not spontaneously drive HCC in animal models. Despite many advances in cancer genetics that include identifying the dominant role of TGF-β signaling in gastrointestinal cancers, we have not reached an integrated view of genetic mutations, copy number changes, driver pathways, and animal models that support effective targeted therapies for these common and lethal cancers. Moreover, pathways involved in stem cell transformation into gastrointestinal cancers remain largely undefined. Identifying the key mechanisms and developing models that reflect the human disease can lead to effective new treatment strategies. In this review, we dissect the evidence obtained from mouse and human liver regeneration, and mouse genetics, to provide insight into the role of TGF-β in regulating the cancer stem cell niche. (Hepatology Communications 2017;1:477-493).

A SMAD4 mutation indicative of juvenile polyposis syndrome in a family previously diagnosed with Menetrier's disease

BACKGROUND

Menetrier's disease (MD) is a rare disease with unknown aetiology, characterized by hypertrophic folds within the fundus and body of the stomach.

AIMS

We investigated mutations of the candidate genes SMAD4, BMPR1A, TGF-α, and PDX1 within a family with MD.

METHODS

A large 4-generation family with MD was identified. This family had 5 cases of MD, 1 case of MD and juvenile polyposis syndrome (JPS) and 3 cases of JPS. Participants provided saliva for DNA extraction and completed a health questionnaire designed to assess conditions that may be found in patients with MD. Following pedigree analysis, we sequenced the coding regions of the SMAD4 and BMPR1A genes and the regulatory regions of the TGF-α and PDX1 genes in affected and non-affected family members.

RESULTS

No mutations were identified in the sequenced regions of BMPR1A, TGF-α, or PDX1. A dominant 1244_1247delACAG mutation of SMAD4 was identified in each of the subjects with JPS as well as in each of the subjects with MD. Although this mutation segregated with disease, there were also unaffected/undiagnosed carriers.

CONCLUSION

The 1244_1247delACAG mutation of SMAD4 is the cause of JPS and the likely cause of MD in a large family initially diagnosed with MD.

Familial juvenile polyposis syndrome with a novel SMAD4 germline mutation

Juvenile polyposis syndrome (JPS) is a dominantly inherited disorder characterized by the development of numerous juvenile polyps (JPs) of the gastrointestinal tract, and associated with a mutation of the SMAD4 or BMPR1A gene. Here, we report a mother-daughter case of familial JPS. A 29-year-old female patient with severe iron deficiency anemia and hypoproteinemia had numerous polyps in the stomach and a few polyps in the ileum and colon that were detected endoscopically. Biopsy specimens from the gastric polyps were diagnosed as JPs. The patient underwent a laparoscopy-assisted total gastrectomy, and her anemia and hypoproteinemia improved. Her mother also had multiple JPs in the stomach, duodenum, jejunum, and colon. We then diagnosed them as having familial JPS. Moreover, germline mutation analysis of the 2 patients presented a novel pathogenic SMAD4 variant.