RT Book, Section A1 Jameson, J. Larry A1 Fauci, Anthony S. A1 Kasper, Dennis L. A1 Hauser, Stephen L. A1 Longo, Dan L. A1 Loscalzo, Joseph SR Print(0) ID 1167064433 T1 Cancer of Unknown Primary Site T2 Harrison's Manual of Medicine, 20e YR 2020 FD 2020 PB McGraw-Hill Education PP New York, NY SN 9781260455342 LK accessmedicine.mhmedical.com/content.aspx?aid=1167064433 RD 2024/03/29 AB Cancer of unknown primary site (CUPS) is defined as follows: biopsy-proven malignancy; primary site unapparent after history, physical examination, chest x-ray, abdominal and pelvic CT, complete blood count, chemistry survey, mammography (women), β-human chorionic gonadotropin (hCG) levels (men), α-fetoprotein (AFP) levels (men), and prostate-specific antigen (PSA) levels (men); and histologic evaluation not consistent with a primary tumor at the biopsy site. About 90% of CUPS tumors are adenocarcinomas (60% well or moderately–well differentiated; 30% poorly differentiated), 5% squamous cell, 2% neuroendocrine, and 3% undifferentiated malignancy. CUPS incidence is declining, probably because of better pathology diagnostic criteria; it accounts for about 3% of all cancers today, down from 10–15% 15 years ago. Most pts are age >60. The tumors are often aneuploid. Cell lines derived from such tumors frequently have abnormalities in chromosome 1.