Solid renal tumor severity in von Hippel Lindau disease is related to germline deletion length and location

Study comparing two types of screening provision for people with von Hippel-Lindau disease

Patients diagnosed with von Hippel-Lindau disease (vHL) require life-long surveillance for this multi-system disease. It is therefore important to assess the comprehensiveness of screening provision, as well as identify what type of screening service is most likely to encourage regular patient attendance. This descriptive study reports on two types of screening service: single appointment One Stop (OS) clinics and multiple appointment Ad Hoc (AH) clinics. One hundred and seventeen vHL patients from eight regional genetics centres were approached to take part. Seventy-two (61.5%) returning a completed study questionnaire: fifty-four (75%) were screened at OS clinics and eighteen (25%) at AH clinics. Comprehensiveness of screening, attendance rates, patient ratings of quality of care and levels of psychological morbidity were compared between the two types of service. While levels of disease severity were similar in patients screened at OS and AH clinics, those seen at OS clinics were screened for twice as many site-specific vHL manifestations compared to those seen at AH clinics (P < 0.0001). More patients at OS clinics regularly attended their screening appointments compared to those at AH clinics (P = 0.0045). There was no difference in the quality of care reported by patients attending the two types of screening service and few problems were reported. Twenty-nine percent of respondents were categorised as clinically anxious and 13% as clinically depressed. These findings suggest that an optimum vHL screening service is one based on OS clinics offering regular comprehensive surveillance and psychological support.

Mitochondrial disorders in renal tumors

As early as 1930, Warburg discovered that metabolic alterations were associated with carcinogenesis and that cancer cells fermented even in the presence of oxygen using glycolysis to fulfill their energy needs, though less efficiently than with respiration. The kidney requiring a very active energy production for its pumping functions has a high mitochondrial activity. Kidney tumors can exist either in relatively benign forms, as for example, in oncocytomas that are crowded with mitochondria or in very aggressive forms such as in clear cell renal carcinomas that exhibit strongly down-regulated mitochondrial activities. These carcinomas can produce metastases that are resistant to anti-mitotic drugs and current treatments only delay the fatal issue. In this review, the mitochondrial alterations observed in various forms of renal tumors will be discussed with the aim of understanding how the knowledge of mitochondrial impairment mechanisms could be helpful to develop new anti-cancer strategies.

Second hit deletion size in von Hippel-Lindau disease

von Hippel-Lindau (VHL) disease is caused by germline mutations of the VHL tumor suppressor gene. Affected individuals are predisposed to development of multiple neoplastic and preneoplastic lesions of different organs. A "second hit," which is usually represented by deletion in the wild-type VHL allele at 3p25, is necessary for initiation of tumor formation. The impact of the size of this deletion is thought to be critical, because other tumor suppressor genes are located nearby, but this has not yet been studied in detail. We mapped the deletion size of the "second hit" in microdissected tissue from 16 different VHL-associated lesions from the same patient using 10 polymorphic chromosome 3 markers. We found that the deletion size is highly variable, ranging from short deletions around the VHL gene to complete loss of the chromosome 3. The deletion sizes are not correlated with the site of the germline mutation, the affected organ, or the type or biological behavior of the tumor. Even preneoplastic cystic structures may harbor entire loss of the chromosome 3, suggesting that loss of VHL gene function alone is not immediately causative for neoplastic growth, but further events, either mutations and deletions in other chromosomes or epigenetic or other than genetic phenomena, are required for tumor formation.

Multifocal renal oncocytoma in a patient with Von Hippel-Lindau mutation

Von Hippel-Lindau disease (VHL) is a rare genetic disease with a lifetime risk of clear cell renal cell carcinoma in approximately 70% of cases. We present a case of a 63-year-old man with bilateral, multifocal renal masses. Genetic testing results were consistent with a VHL deletion. The patient had no other disease manifestations consistent with VHL. The patient underwent staged bilateral nephron-sparing procedures. Pathology of all renal masses revealed oncocytoma. To our knowledge, we describe the first reported case of multiple renal oncocytomas in a male patient with a germline VHL mutation.

Molecular genetics of familial renal cell carcinoma syndromes

RCC represents a group of clinically and genetically diverse diseases. Familial RCC syndromes, although rare, provide an invaluable model to study the molecular mechanisms of renal carcinogenesis. Many causative oncogenes and tumor suppressor genes have been identified and it is now possible to identify the affected individuals and carriers by genetic testing. Understanding of the molecular pathways of these genes will have a significant impact on the diagnosis and treatment of familial and sporadic RCC.

Inclusion of Scar/WAVE3 in a similar complex to Scar/WAVE1 and 2

BACKGROUND

The Scar/WAVE family of proteins mediates signals to actin assembly by direct activation of the Arp2/3 complex. These proteins have been characterised as major regulators of lamellipodia formation downstream of Rac activation and as members of large protein complexes.

RESULTS

We have investigated the interactions of the three human Scar/WAVE isoforms with several previously described binding partners for Scar/WAVE 1 or 2. We find that all three Scar/WAVE isoforms behave similarly and are likely to participate in the same kinds of protein complexes that regulate actin assembly.

CONCLUSION

Differences between Scar/WAVE proteins are therefore likely to be at the level of tissue distribution or subtle differences in the affinity for specific binding partners.