ABSTRACT
Updated from their original publication in 2004, these cancer genetic counseling recommendations describe the medical, psychosocial, and ethical ramifications of counseling at-risk individuals through genetic cancer risk assessment with or without genetic testing. They were developed by members of the Practice Issues Subcommittee of the National Society of Genetic Counselors Familial Cancer Risk Counseling Special Interest Group. The information contained in this document is derived from extensive review of the current literature on cancer genetic risk assessment and counseling as well as the personal expertise of genetic counselors specializing in cancer genetics. The recommendations are intended to provide information about the process of genetic counseling and risk assessment for hereditary cancer disorders rather than specific information about individual syndromes. Essential components include the intake, cancer risk assessment, genetic testing for an inherited cancer syndrome, informed consent, disclosure of genetic test results, and psychosocial assessment. These recommendations should not be construed as dictating an exclusive course of management, nor does use of such recommendations guarantee a particular outcome. These recommendations do not displace a health care provider's professional judgment based on the clinical circumstances of a client.
Subject(s)
Genetic Counseling , Genetic Testing , Neoplasms/genetics , Risk Assessment , Genetic Predisposition to Disease , Humans , WorkforceABSTRACT
BACKGROUND: Physiologic iodide-uptake, mediated by the sodium/iodide symporter (NIS), in the salivary gland confers its susceptibility to radioactive iodine-induced damage following (131)I treatment of thyroid cancer. Subsequent quality of life for thyroid cancer survivors can be decreased due to recurrent sialoadenitis and persistent xerostomia. NIS expression at the three principal salivary duct components in various pathological conditions was examined to better our understanding of NIS modulation in the salivary gland. METHODS: NIS expression was evaluated by immunohistochemistry in human salivary gland tissue microarrays constructed of normal, inflamed, and neoplastic salivary tissue cores. Cumulative (123)I radioactivity reflecting the combination of NIS activity with clearance of saliva secretion in submandibular and parotid salivary glands was evaluated by single-photon emission computed tomography/computed tomography imaging 24 hours after (123)I administration in 50 thyroid cancer patients. RESULTS: NIS is highly expressed in the basolateral membranes of the majority of striated ducts, yet weakly expressed in few intercalated and excretory duct cells. The ratio of (123)I accumulation between parotid and submandibular glands is 2.38±0.19. However, the corresponding ratio of (123)I accumulation normalized by volume of interest is 1.19±0.06. The percentage of NIS-positive striated duct cells in submandibular salivary glands was statistically greater than in parotid salivary glands, suggesting a higher clearance rate of saliva secretion in submandibular salivary glands. NIS expression in striated ducts was heterogeneously decreased or absent in sialoadenitis. Most ductal salivary gland tumors did not express NIS. However, Warthin's tumors of striated duct origin exhibited consistent and intense NIS staining, corresponding with radioactive iodine uptake. CONCLUSIONS: NIS expression is tightly modulated during the transition of intercalated to striated ducts and striated to excretory ducts in salivary ductal cells. NIS expression in salivary glands is decreased during inflammation and tumor formation. Further investigation may identify molecular targets and/or pharmacologic agents that allow selective inhibition of NIS expression/activity in salivary glands during radioactive iodine treatment.