Birt‐Hogg‐Dubé syndrome‐associated renal cell carcinoma: Histopathological features and diagnostic conundrum

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. Most cases of BHD syndrome‐associated RCC (BHD‐RCC) are less aggressive than sporadic clear cell RCC and multifocal. Therefore, it is critical to distinguish BHD‐RCC from its sporadic counterparts to identify and monitor affected families and to preserve renal function for as long as possible. The World Health Organization/International Society of Urological Pathology consensus classification defined distinct entities for certain hereditary RCC; however, BHD‐RCC was not included in this classification. Although the clinical features and molecular mechanisms of BHD‐RCC have been investigated intensively over the last two decades, pathologists and urologists occasionally face difficulties in the diagnosis of BHD‐RCC that require genetic testing. Affected patients usually have miscellaneous benign disorders that often precede renal carcinogenesis. In the present review, we summarize the current understanding of the histopathological features of BHD‐RCC based on our epidemiological studies of Japanese families and a literature review. Pathological diagnostic clues and differential diagnosis of BHD‐RCC from other hereditary RCC are also briefly discussed.     

Genetic predisposition to kidney cancer

Kidney cancer is not a single disease but is made up of a number of different types of cancer classified by histology that are disparate in presentation, clinical course, and genetic basis. Studies of families with inherited renal cell carcinoma (RCC) have provided the basis for our understanding of the causative genes and altered metabolic pathways in renal cancer with different histologies. Von Hippel-Lindau disease was the first renal cancer disorder with a defined genetic basis. Over the next two decades, the genes responsible for a number of other inherited renal cancer syndromes including hereditary papillary renal carcinoma, Birt-Hogg-Dube´syndrome, hereditary leiomyomatosis and renal cell carcinoma, and succinate dehydrogenase–associated renal cancer were identified. Recently, renal cell carcinoma has been confirmed as part of the clinical phenotype in individuals from families with BAP1-associated tumor predisposition syndrome and MiTF-associated cancer syndrome. Here we summarize the clinical characteristics of and causative genes for these and other inherited RCC syndromes, the pathways that are dysregulated when the inherited genes are mutated, and recommended clinical management of patients with these inherited renal cancer syndromes.     

Genetic diagnosis of Lynch syndrome II in an extended colorectal cancer-prone family

Knowledge of colon cancer genetics, with particular attention to precision in hereditary cancer syndrome diagnosis, can often enable highly targeted surveillance and management strategies for patients at high genetic risk. Unfortunately, the patient's family history of cancer is often given minimal attention, and knowledge of hereditary cancer syndromes is frequently limited. Indeed, many physicians still consider familial adenomatous polyposis (FAP) as the only genetic risk factor for colorectal cancer. This concern with FAP was noted in a colorectal cancer-prone kindred which for decades had been thought to manifest that syndrome. However, after meticulous genetic, medical, and pathologic studies, the cardinal phenotypic characteristics of Lynch syndrome II were observed. The potential for cancer control in current and future generations of families like this one clearly mandates the need for computerized registries which could transmit current information about hereditary colon cancer syndrome diagnosis, surveillance, and management.     

Molecular basis for the treatment of renal cell carcinoma

Renal cell carcinoma (RCC) is a heterogeneous malignancy whose incidence rate has notably increased in recent years without any evident reason. Traditionally, RCC has been resistant to classic treatments (chemotherapy, radiotherapy and hormonal therapy), with only a small percentage of patients benefiting from cytokine therapy. Different hereditary syndromes have been associated with RCC, Von Hippel Lindau (VHL) being the most important syndrome. Understanding key molecular pathways implicated in the tumorigenesis of RCC has crystallised in the development of more effective therapies. Specifically, drugs targeting VEGF (bevacizumab, sunitinib, sorafenib, axitinib, pazopanib) and PI3K-mTOR (temsirolimus and everolimus) have become the cornerstone of renal cancer treatment.     

Genetic testing by cancer site: urinary tract

ABSTRACT: The roles of renal cell carcinoma (RCC) and urothelial cancers of the upper urinary tract are often overlooked as indicators for genetic risk assessment. The key features of 5 hereditary cancer susceptibility conditions involving an increased risk for RCC are discussed. von Hippel-Lindau disease, hereditary papillary RCC, and hereditary leiomyomatosis and RCC each predispose to a specific histological type of RCC, whereas Birt-Hogg-Dubé and hereditary paraganglioma/pheochromocytoma entail a variety of histologic findings. Familiarity with the rare or uncommon clinical features associated with these conditions, such as cutaneous neoplasms, paraganglioma/pheochromocytoma, and recurrent spontaneous pneumothoraces, aids in identifying patients with an underlying RCC susceptibility. A path to identifying syndromic cases lies in thorough investigation of the patient's medical history, their family history, and the histological type of RCC reported in the family. A guide to genetic predisposition testing for RCC is proposed. Upper urinary tract cancers in Lynch syndrome are also discussed.     

Hereditary colorectal cancer syndromes: molecular genetics, genetic counseling, diagnosis and management

Hereditary forms of colorectal cancer, as is the case with virtually all forms of hereditary cancer, show extensive phenotypic and genotypic heterogeneity, a phenomenon discussed throughout this special issue of Familial Cancer. Clearly, the family physician, oncology specialist, genetic counselor, and cancer geneticist must know fully the complexity of hereditary cancer syndromes, their differential diagnosis, in order to establish a diagnosis, direct highly-targeted surveillance and management, and then be able to communicate effectively with the molecular geneticist so that an at-risk patient’s DNA can be tested in accord with the syndrome of concern. Thus, a family with features of the Lynch syndrome will merit microsatellite instability testing, consideration for immunohistochemistry evaluation, and mismatch repair gene testing, while, in contrast, a patient with FAP will require APC testing. However, other germline mutations, yet to be identified, may be important should testing for these mutations prove to be absent and, therein, unrewarding to the patient. Nevertheless, our position is that if the patient’s family history is consistent with one of these syndromes, but a mutation is not found in the family, we still recommend the same surveillance and management strategies for patients from families with an established cancer-causing germline mutation. Our purpose in this paper is to provide a concise coverage of the major hereditary colorectal cancer syndromes, to discuss genetic counseling, molecular genetic evaluation, highly targeted surveillance and management, so that cancer control can be maximized for these high hereditary cancer risk patients.     

Genetically engineered mouse models for hereditary cancer syndromes

Advances in molecular diagnostics have led to improved diagnosis and molecular understanding of hereditary cancers in the clinic. Improving the management, treatment, and potential prevention of cancers in carriers of predisposing mutations requires preclinical experimental models that reflect the key pathogenic features of the specific syndrome associated with the mutations. Numerous genetically engineered mouse (GEM) models of hereditary cancer have been developed. In this review, we describe the models of Lynch syndrome and hereditary breast and ovarian cancer syndrome, the two most common hereditary cancer predisposition syndromes. We focus on Lynch syndrome models as illustrative of the potential for using mouse models to devise improved approaches to prevention of cancer in a high-risk population. GEM models are an invaluable tool for hereditary cancer models. Here, we review GEM models for some hereditary cancers and their potential use in cancer prevention studies.     

Novel germline mutations in FLCN gene identified in two Chinese patients with Birt–Hogg–Dubé syndrome

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). Few BHD syndrome cases have been reported in Asian countries, and cutaneous presenta-tions are relatively rare in Asian patients. Asian BHD patients may be misdiagnosed due to their atypical manifesta-tions. Here, we report two Chinese BHD patients with novel FLCN mutations (c.946-947delAG in exon 9 and c.770-772delCCT in exon 7). Both of them had RCC and spontaneous pneumothorax without fibrofolliculomas. In patients with RCC and pulmonary cysts but without cutaneous lesions, screening for mutations in the FLCN gene should be performed, especially for those with a family history of RCC or pulmonary cysts (pneumothorax).     

Genetic testing by cancer site: skin

ABSTRACT: Many hereditary cancer predisposition syndromes are associated with cutaneous findings, both benign and malignant. Dermatological examination and histopathology, when combined with a thorough personal and family medical history, play an important role in the diagnosis of cancer predisposition syndromes. Skin findings are an important diagnostic tool for a variety of cancer syndromes, including Cowden syndrome, Birt-Hogg-Dubé, hereditary leiomyomatosis renal cell carcinoma, and others. This article focuses on the phenotype, medical management, and genetic testing for 4 hereditary cancer syndromes that include cutaneous findings: hereditary melanoma, basal cell nevus syndrome, neurofibromatosis type 1, and neurofibromatosis type 2.     

Hereditary Cancer

Cancer cases are often clustered in certain families and pedigree analysis indicates that at least 5% of cancer patients have a genetic predisposition to the disease. During the past decade the basic mechanisms for hereditary cancer have been outlined and a large number of the genes involved have been identified. This rapid development has changed the clinical management of cancer families, which now includes surveillance programs directed to early diagnosis of tumors as well as predictive mutation testing to identify gene carriers. This review outlines the molecular basis for hereditary cancer that has become the basis for genetic counseling of cancer families. The organization of clinics for cancer families in Sweden and the clinical implications of surveillance programs and gene testing for cancer predisposition are discussed.     

The ODAC Chronicles: Part 6a. ODAC’s structure and function

Lynch syndrome, also known as hereditary nonpolyposis colorectal cancer, is the most common form of hereditary colorectal cancer. It is characterized by early onset of colorectal cancer and other extracolonic-associated malignancies. This disorder is inherited in an autosomal dominant pattern and is due to a mutation in one of the DNA mismatch repair genes. Although clinical and molecular understanding of the syndrome has progressed dramatically in the last decade, diagnosis of the syndrome is still a clinical challenge. This review summarizes the main features of the syndrome and provides an update of its management.     

Lynch syndrome in colorectal cancer patients

Lynch syndrome, also known as hereditary nonpolyposis colorectal cancer, is the most common form of hereditary colorectal cancer. It is characterized by early onset of colorectal cancer and other extracolonic-associated malignancies. This disorder is inherited in an autosomal dominant pattern and is due to a mutation in one of the DNA mismatch repair genes. Although clinical and molecular understanding of the syndrome has progressed dramatically in the last decade, diagnosis of the syndrome is still a clinical challenge. This review summarizes the main features of the syndrome and provides an update of its management.     

Cancer screening guidelines and prevention factors for high-risk patients with a family history of colorectal cancer

Family history of colorectal cancer or of adenomas may confer significant risk of colorectal cancer. Ideally, diagnosis of an inherited syndrome such as familial adenomatous polyposis (FAP) or hereditary nonpolyposis colorectal cancer (HNPCC) enables a molecular biology-driven approach to screening and management. When no hereditary syndrome can be established, clinicians must rely on empiric risk estimates and offer screening accordingly. Detailed rationale and guidelines for use of syndrome characteristics including genetic testing, counseling, and selection of surveillance tools are discussed.     

Is breast cancer a part of Lynch syndrome?

ABSTRACT: A long-standing question is whether breast cancer is an integral part of Lynch syndrome, also known as hereditary non-polyposis colorectal cancer. A recent study by Lotsari and colleagues analyzes molecular features of breast cancers from families with Lynch syndrome, including germline mutation carriers and their non-mutation carrier siblings, and controls with sporadic breast cancer. The study finds microsatellite instability and loss of mismatch DNA repair protein expression in one third and two thirds of Lynch syndrome samples, respectively, but in none of the non-mutation carriers or controls. Overall, the age of diagnosis of breast cancer in Lynch syndrome mutation carriers is no different than that in non-carriers, but diagnosis age was lower in those carriers whose breast tumors exhibited defects in mismatch repair. These results have important implications for genetic counseling and genetic testing of families with breast cancer and other tumors associated with Lynch syndrome, such as colorectal and endometrial cancers.     

No evidence for a genetic modifier for renal cell cancer risk in HLRCC syndrome

Hereditary leiomyomatosis and renal cell cancer (HLRCC) is a tumor predisposition syndrome caused by heterozygous germline mutations in the fumarate hydratase (FH) gene. Cutaneous and uterine leiomyomas are the most common clinical manifestations of HLRCC, whereas only approximately 20% of the families display renal cell cancer (RCC). The number of RCC cases in these families varies from one to five. Interestingly, families with multiple RCC cases are mainly found in Finland and the USA. Such aggregation of RCC in only some families and populations has led to the hypothesis that besides FH mutations also other inherited genetic and/or environmental factors may contribute to the malignant kidney tumor formation. To search for such a genetic modifier we have performed a genome-wide linkage analysis in two and an identical by descent analysis in four Finnish HLRCC families with several RCC patients. Additional Finnish and French families were used in fine-mapping and haplotype analyses. The only region compatible with linkage was the locus surrounding the FH gene itself in chromosome 1q43. The genes in the putative candidate region were screened, but no potentially pathogenic alterations were observed. Although these data do not rule out the existence of a genetic modifier, they emphasize the contribution of the FH genotype in HLRCC related RCC. Therefore, as all FH mutation carriers may have an increased risk for developing renal cancer, counseling and genetic testing should be offered for all HLRCC family members and clinical follow-up should be organized for the mutation carriers.     

Lynch 综合征的诊治进展和家系管理*

Lynch 综合征（Lynch syndrome,LS）是遗传性结直肠癌中最常见（约占5%）的一类常染色体显性遗传病,错配修复基因的种系突变和微卫星不稳定是其区别于其他遗传性结直肠癌的两大特点。近年来,研究发现在诊断和治疗上,LS与散发性结直肠癌有一定的区别;此外除了患者本人的诊断和治疗,整个家系的管理也至关重要。此类疾病应当引起临床高度重视。本文对LS的最初定义、诊断标准和筛查标准的变迁、最新治疗进展和家系管理进行综述,旨在帮助临床了解LS,给予患者合理的治疗,以及对其家系成员适当的干预和监控,尽可能降低患癌风险。      

Hereditary cancer syndrome diagnosis: molecular genetic clues and cancer control

Oncologists who are aware of the progress in hereditary cancer syndrome diagnosis, and, in particular, of how this effort may be effectively facilitated through a comprehensive family history in concert with molecular genetic studies, are in the envious position of designing highly targeted screening and management programs for the membership of these cancer-prone families. The Lynch syndrome is discussed as a clinical model wherein the presence of mismatch repair mutations provides a high level of diagnostic certainty for the initiation of targeted cancer screening and management. The familial atypical multiple mole melanoma-pancreatic cancer (FAMMM-PC) syndrome, on the other hand, provides another model with cancer-control potential. Given its phenotypic features of multiple atypical nevi, high total body mole count and cutaneous malignant melanoma, coupled with the integral association of PC in a subset of FAMMM kindreds with the CDKN2A germline mutation, this may result in a perhaps lower level of diagnostic certainty when compared with the Lynch syndrome. This knowledge may impact upon progress in the earlier diagnosis of melanoma and provide an impetus for creative diagnostic methods in PC, a disease that, at this time, demonstrates a mortality rate virtually identical to its incidence rate.     

Familial renal cancer as an indicator of hereditary leiomyomatosis and renal cell cancer syndrome

Hereditary Leiomyomatosis and Renal Cell Carcinoma (HLRCC) is a hereditary condition which typically presents with cutaneous and uterine leiomyomata. Papillary type II renal cell carcinoma and other less common histologic subtypes of renal cancer have been reported in HLRCC. We describe the case of a 31-year-old man in which the pathology review of his renal carcinoma and a positive family history of renal carcinoma allowed for the identification of a pathogenic mutation in the FH gene (c.698G>A;p.R233H) confirming the diagnosis of HLRCC. Recognition of this syndrome allowed for appropriate surveillance as well as identification of at-risk family members. Pathology review is essential for accurate diagnosis of a hereditary cancer syndrome in the setting of familial renal cancer.     

Familial Pancreatic Cancer

The dismal prognosis of ductal pancreatic adenocarcinoma is mainly attributable to advanced tumor stages at the time of diagnosis. Meanwhile, familial pancreatic cancer is an established hereditary tumor entity that is responsible for approximately 3% of pancreatic cancer (PC) cases. Therefore, analysis of the family history may help to identify individuals at increased risk of developing PC. These include members of families with a history of PC as well as those of families with distinct hereditary cancer syndromes such as Peutz-Jeghers syndrome, hereditary pancreatitis, familial atypical multiple mole melanoma syndrome, hereditary breast and ovarian cancer syndrome and hereditary non-polyposis colorectal cancer. In future, the identification of germline mutations in genes predisposing to PC, together with the analysis of exogenous risk factors, could be used for a more precise risk assessment for the development of PC. This may allow the application of invasive screening methods for the identification of early PC or, even better, its precursor lesions in high-risk individuals, providing the option of timely curative pancreatectomy.