Cancer-associated genodermatoses: a personal history

Oral Manifestations and Molecular Basis of Oral Genodermatoses: A Review

Genodermatoses refers to group of inherited monogenic disorders with skin manifestations. Many of these disorders are rare and also have oral manifestations, called oral genodermatoses. This article provides a focused review of molecular basis of important genodermatoses that affects the oral cavity and also have prominent associated dermatologic features. In several conditions discussed here, the oral findings are distinct and may provide the first clue of an underlying genetic diagnosis. The article also emphasises on the prenatal diagnosis, genetic counselling and the treatment oral genodermatoses.

Basal cell nevus syndrome: clinical and molecular review and case report

Basal cell nevus syndrome (BCNS), also referred to as nevoid basal cell carcinoma syndrome or Gorlin-Goltz syndrome, was first described by Gorlin and Goltz in 1960 as an autosomal dominant disorder characterized by the early appearance of multiple basal cell carcinomas (BCCs), keratocysts of the jaw, ectopic calcifications, palmar and plantar pits, and anomalies of the ocular, skeletal, and reproductive systems. The genesis of this cancer's etiology in relation to BCNS was unclear until a few years ago when molecular analysis studies suggested a relationship between BCC and the loss-of-function mutations of the patched gene (PTCH) found on chromosome arm 9q. PTCH inhibits signaling by the membrane protein Smoothened (Smo), and this inhibition is relieved by binding sonic hedgehog (SHH) to PTCH. We describe a patient with multiple BCCs associated with x-ray anomalies of BCNS and review the basis of the SHH signaling pathway and clinical aspects of BCNS.

Facial papules as a marker of internal malignancy

Facial papules (bumps) confront the general practitioner during every face-to-face meeting with the patient. Increased awareness and recognition of the facial papules that represent cutaneous signs of internal malignancy will allow an early, aggressive workup and treatment of any associated cancer. This article details the clinical presentation, etiology, pathologic findings, and associated malignancy for such presentations. A skin biopsy for histopathologic diagnosis is necessary to distinguish these clues to underlying malignancy from the numerous benign lesions that cause facial papules.

A case of Cowden's syndrome presenting with gastric carcinomas and gastrointestinal polyposis

BACKGROUND

A 73-year-old white man was referred to a cancer genetics clinic for evaluation of a approximately 20-year history of mixed upper and lower gastrointestinal polyposis, including hyperplastic, inflammatory and adenomatous polyps, colonic ganglioneuromas, and associated diffuse, esophageal glycogenic acanthosis. Two synchronous gastric carcinomas had been identified before referral and the patient had undergone a total gastrectomy, omentectomy and cholecystectomy. Multiple hyperplastic polyps and small, sessile polyps were also observed in the gastrectomy specimen.

INVESTIGATIONS

History and physical examination, upper and lower gastrointestinal endoscopy and biopsy, genetic testing, molecular pathology investigations (immunohistochemistry), thyroid ultrasonography, fine-needle aspiration of a thyroid nodule.

DIAGNOSIS

Cowden's syndrome.

MANAGEMENT

Genetic counseling, thyroidectomy, vitamin B(12) supplementation, continued endoscopic surveillance and genetic testing of at-risk family members.

Lessons from the skin--cutaneous features of familial cancer

As the molecular basis of disease continues to be elucidated, familial cancer syndromes, which consist of a range of neoplastic and non-neoplastic features, are emerging. The usual pathway of referral to a genetics clinic or familial cancer centre is via an oncologist, when high-risk features that suggest a possible hereditary basis for the presenting cancer are recognised. Traditionally, these high-risk features include more than two family members with similar cancers over two or more generations, a young age of onset, and more than one synchronous or metachronous tumour. These features are effective in ascertaining a substantial proportion of families with hereditary breast and ovarian cancer due to a BRCA mutation, or the more common bowel-cancer predisposition syndromes, such as hereditary non-polyposis colon cancer and familial adenomatous polyposis. However, there are a range of familial cancer syndromes that are not easily detected and that can remain undiagnosed when history and examination are not extended to include non-malignant features. The identification of cutaneous signs associated with rare familial-cancer syndromes provides individuals and their families with the opportunity to undertake early surveillance for malignant and non-malignant complications that might in time be shown to improve outcomes.

Oral manifestations of internal malignancy and paraneoplastic syndromes

Malignant tumors of visceral organs are a fundamental feature of familial cancer and paraneoplastic syndromes. In many instances, the presence of an internal and often occult malignancy may be forewarned by various external manifestations. Several of these findings are preferentially localized to the head and neck region, including the oral cavity proper. This places the dental practitioner in a unique position to detect these "markers" of occult neoplastic involvement. Because these markers may present before an established syndrome or cancer diagnosis, even representing the first expression of disease in some cases, early recognition by a dentist may lead to timely diagnosis and management of these cancer-associated syndromes.

Lessons learned from DNA repair defective syndromes

Genomic instability is the driving force behind cancer development. Human syndromes with DNA repair deficiencies comprise unique opportunities to study the clinical consequences of faulty genome maintenance leading to premature aging and premature cancer development. These syndromes include chromosomal breakage syndromes with defects in DNA damage signal transduction and double-strand break repair, mismatch repair defective syndromes as well as nucleotide excision repair defective syndromes. The same genes that are severely affected in these model diseases may harbour more subtle variations in the 'healthy' normal population leading to genomic instability, cancer development, and accelerated aging at later stages of life. Thus, studying those syndromes and the molecular mechanisms behind can significantly contribute to our understanding of (skin) cancerogenesis as well as to the development of novel individualized preventive and therapeutic anticancer strategies. The establishment of centers of excellence for studying rare genetic model diseases may be helpful in this direction.