Introduction

It is estimated that greater than 5% of all colorectal cancers (CRCs) can be directly linked to a specific, inherited allele. The ''polyposis syndromes,'' which are further subdivided into adenomatous and hamartomatous syndromes, comprise approximately 1% of these hereditary cancers.[1] The adenomatous polyposis syndromes consist of familial adenomatous polyposis (FAP) and attenuated FAP. The hamartomatous polyposis syndromes predominantly include Peutz-Jeghers syndrome (PJS), juvenile polyposis, and Cowden syndrome. The genetic etiologies responsible for significant subsets of these disorders have been previously identified.[2]

Peutz-Jeghers syndrome (PJS) is a rare, inherited syndrome characterized by gastrointestinal polyposis and mucocutaneous pigmentation. The histologically distinct polyps of PJS occur throughout the GI tract, but are most consistently found in the jejunum, ileum, and duodenum. Individuals with PJS are at risk for numerous intestinal and extraintestinal malignancies, including small bowel, stomach, breast, and gonadal tumors.[3] In the late 1990s, the genetic etiology of PJS was described by two groups of investigators.[4,5] Germline mutations in a serine/threonine kinase designated STK11 (also known as LKB1), which functions as a tumor suppressor, are likely responsible for roughly half of PJS cases.[6]

This chapter discusses the clinical and genetic aspects of PJS, including the function of the STK11 gene product, and lists the specific mutations that have been described to date. Special attention is paid to available genetic testing and current surveillance recommendations.

Getting Started With Dumbbells

Getting Started With Dumbbells

The use of dumbbells gives you a much more comprehensive strengthening effect because the workout engages your stabilizer muscles, in addition to the muscle you may be pin-pointing. Without all of the belts and artificial stabilizers of a machine, you also engage your core muscles, which are your body's natural stabilizers.

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