Birt-Hogg-Dubé (BHD) syndrome is associated with the development of hereditary renal cell carcinoma (RCC) and is caused by a germline mutation in the folliculin gene.
Here we report a case of a 14 year-old patient with germline FLCN mutation leading to an early-onset bulky RCC that could not be classified strictly according to existing histological types.
Birt-Hogg-Dubé (BHD) syndrome, a hereditary renal cancer syndrome caused by mutations in the folliculin (FLCN) gene, is characterized by the presence of fibrofolliculomas, pulmonary cysts, spontaneous pneumothorax, and renal cell carcinoma (RCC).
Recent studies indicated that FNIP1/FNIP2 double knockout mice display enlarged polycystic kidneys and renal carcinoma, which phenocopies FLCN knockout mice, suggesting that these two proteins function together to suppress renal cancer.
We further demonstrated that the mTOR inhibitor, sirolimus, suppresses the tumor's growth, suggesting that mTOR inhibitors might be effective in control of FLCN-deficient RCC, especially in BHD renal tumorigenesis.
To explore therapeutic approaches to renal cell carcinoma in patients with Birt-Hogg-Dubé syndrome we investigated the anticancer effects of irradiation on folliculin deficient renal cancer cells.
In a search for potential synthetic-lethal targets for FLCN using a phosphatase siRNA library screening approach, we found that knockdown of SSH2 serine phosphatase (one of the three members of Slingshot family and previously implicated in actin reorganization) specifically induced Caspase3/7 activity in a dose-dependent manner (up to six-fold increase, 10 nM, 72 h) in two human FLCN-deficient cell lines (BHD-origin renal cell carcinoma UOK257 and thyroid carcinoma FTC133) but not in their folliculin expressing isogenic cell lines.
These findings define FLCN as a player in HIF-dependent longevity signaling and connect organismal aging, stress resistance, and regulation of longevity with the formation of renal cell carcinoma.
We demonstrate that VHL regulates expression of FLCN at the mRNA and protein levels in RCC cell lines, and that FLCN protein expression is decreased in human ccRCC tumors with VHL loss, as compared with matched normal kidney tissue.
It is known that mutation of FLCN can predispose Birt-Hogg-Dubé (BHD) patient's to renal cell carcinoma , renal and lung cysts, as well as skin fibrofolliculomas.
Thus, several BHD symptoms may be due to abnormal levels of FLCN rather than its complete loss and accordingly, we show expression of mutant FLCN in a BHD-associated renal carcinoma.
To develop therapeutic approaches for renal cell carcinoma (RCC) in BHD syndrome, we adopted a strategy to identify tumor-selective growth inhibition in a RCC cell line with FLCN inactivation.
A bona fide tumour suppressor activity of FLCN was confirmed by nude mouse xenograft assays of two human RCC cell lines with either diminished or re-expressed FLCN.
Germline mutations in a tumor suppressor gene FLCN lead to development of fibrofolliculomas, lung cysts and renal cell carcinoma (RCC) in Birt-Hogg-Dubé syndrome.
The BHD gene (also known as folliculin or FLCN) is the gene for Birt-Hogg-Dube syndrome, an autosomal-dominant genodermatosis associated with a hereditary form of chromophobe and oncocytic, hybrid RCC.
Mutations in a novel gene lead to kidney tumors, lung wall defects, and benign tumors of the hair follicle in patients with the Birt-Hogg-Dubé syndrome.