Thursday, December 30, 2010 (Last Updated: 01/03/2011)
THURSDAY, Dec. 30 (HealthDay News) -- The association of cancer of unknown primary (CUP) with families of kidney, lung, and colorectal cancers suggests a genetic basis and shared metastatic mechanisms by several cancer types, according to a study published online Dec. 28 in the Journal of Clinical Oncology.
Kari Hemminki, M.D., Ph.D., of the German Cancer Research Centre in Heidelberg, and colleagues identified 35,168 patients with CUP in the Swedish Family-Cancer Database and calculated risks between family members for concordant and discordant cancers using standardized incidence ratio (SIR).
The investigators found that familial cases of CUP accounted for 2.8 percent of all CUP cases in the offspring generation. The investigators also found that, when a sibling was diagnosed with CUP, the familial SIR for CUP was 1.69. CUP was associated with lung (SIR, 1.87), kidney (SIR, 1.82), liver (SIR, 1.67), ovarian (SIR, 1.45), colorectal (SIR, 1.26), and breast (SIR, 1.15) cancers as well as melanoma (SIR, 1.26) when there was a discordant relationship between siblings. In addition, upper aerodigestive tract, bladder, pancreatic, and prostate cancers were associated with CUP. The authors write that the association of CUP with lung, colorectal, and kidney cancers suggests that there is a marked genetic basis as well as shared metastatic mechanisms by many types of cancer.
"The present data show that CUP is not a disease of random metastatic cancers but, instead, a disease of a defined set of cancers. The association of CUP with families of kidney, lung, and colorectal cancers suggests a marked genetic basis and shared metastatic mechanisms by many cancer types," the authors write. "Familial sites shared by CUP generally match those arising in tissue-of-origin determinations and, hence, suggest sites of origin for CUP. Mechanistic exploration of CUP may provide insight into defense against primary tumors and the metastatic process."
Hematology & Oncology
Copyright © 2010 HealthDay. All rights reserved.