Loss of heterozygosity on the long arm of human chromosome 7 in sporadic renal cell carcinomas

Cytogenetic and molecular analysis of DNA sequences with highly polymorphic microsatellite markers have implicated allele loss in several chromosomal regions including 3p, 6p, 6q, 8p, 9p, 9q, 11p and 14q in the pathogenesis of sporadic renal cell carcinomas (RCCs). Deletions involving the long arm of chromosome 7 have not been described in RCCs although they have been seen in several other tumor types. However, there have been no detailed analysis of loss of heterozygosity (LOH) of 7q sequences in sporadic RCCs. We therefore studied LOH for DNA sequences on 7q with 10 highly polymorphic markers in 92 matched normal/tumor samples representing sporadic RCCs including papillary, nonpapillary, and oncocytomas in order to determine whether allelic loss could be detected in a tumor type with no visible 7q rearrangements at the cytogenetic level. We found chromosome 7q allele loss in 59 of 92 cases (64%) involving one, two, or more microsatellite markers. The most common allele loss included loci D7S522 (24%) and D7S649 (30%) at 7q31.1-31.2, a region that contains one of the common fragile sites, FRA7G. By comparative multiplex PCR analysis, we detected a homozygous deletion of one marker in the 7q 31.1-31.2 region in one tumor, RC21. These results support the idea that a tumor suppressor gene in 7q31 is involved in the pathogenesis of sporadic renal cell carcinomas.     

Sequence of the FRA3B common fragile region: implications for the mechanism of FHIT deletion

The hypothesis that chromosomal fragile sites may be "weak links" that result in hot spots for cancer-specific chromosome rearrangements was supported by the discovery that numerous cancer cell homozygous deletions and a familial translocation map within the FHIT gene, which encompasses the common fragile site, FRA3B. Sequence analysis of 276 kb of the FRA3B/FHIT locus and 22 associated cancer cell deletion endpoints shows that this locus is a frequent target of homologous recombination between long interspersed nuclear element sequences resulting in FHIT gene internal deletions, probably as a result of carcinogen-induced damage at FRA3B fragile sites.     

Extracellular matrix in renal cell carcinomas

Extracellular matrix (ECM) may be divided into interstitial matrix and the basement membrane (BM). ECM influences a variety of epithelial cell behaviours, including proliferation, differentiation, and morphogenesis, maybe most widely studied in kidney morphogenesis. In carcinomas, including renal cell carcinomas (RCCs), these properties and interactions of cells with interstitial matrix and BM are disturbed. As a carcinoma with a tendency to spread to distant sites, RCC is an interesting target for the study of epithelial-stromal interactions. Among interstitial collagens, type VI collagen appears to be widely distributed in RCCs. Also EDA-fibronectin (EDA-Fn) as well as tenascin-C (Tn) are important stromal components especially in poorly differentiated carcinomas. BMs of RCC islets and those of tumor blood vessel endothelia may merge in poorly differentiated carcinomas. As a dynamic component of BMs, laminins (Ln) are important in kidney development and RCC progression. Type IV collagen and nidogen, other components of BMs in RCCs, are produced by stromal as well as epithelial cells. ECM proteins may function in RCC progression by binding and regulating the activity of growth factors e.g. transforming growth factor beta 1 and basic fibroblast growth factor. Also the expression of cell surface receptors for ECM is disturbed in RCCs. At least alpha v integrin (Int) and CD44 emerge in renal epithelial cells during malignant transformation. Papillary renal neoplasms differ from RCCs by cell adhesion receptor expression and BM composition as well as by ECM avascularity and capacity to bind growth factors, thus suggesting a distinct property for this renal tumor.     

A frequent activated smoothened mutation in sporadic basal cell carcinomas

Basal-cell carcinomas (BCCs) are the most common cancer in Caucasians. It has been reported that the patched gene is inactivated in 30-40% sporadic BCCs and 20% sporadic medulloblastomas via loss of heterozygosity and nonsense mutations. Recently, two activating smoothened mutations have been found in the sporadic basal cell carcinomas. One, at base pair 1604 (G-to-T transversion) of exon 9, changes codon 535 from tryptophan to leucine, and the other, at base pair 1685 (G-to-A transition) of exon 10, changes codon 562 from arginine to glutamine (Xie et al., 1998). In our study, 1604G-->T was found in 20 out of 97 (20.6%) sporadic BCCs. The high prevalence indicates that 1604G is the mutation hot spot in our tumor samples. This mutation was detected in all three histological subtypes of BCCs, suggesting that smoothened mutation is an early event during the development of the tumor. Our finding of a high smoothened mutation rate, together with high frequent patched gene mutations reported recently, indicates that activation of the hedgehog signal transduction pathway is the most common and early event in the development of sporadic BCCs. Additionally, to determine whether smoothened, like patched, is also involved in the carcinogenesis of medulloblastomas, we screened medulloblastoma samples for these two mutations by restriction analysis. We have found the 1604G-->T mutation in 1 out of 21 medulloblastomas. This result confirmed smoothened gene involvement in the carcinogenesis of medulloblastoma.     

Detection of deletions in the short arm of chromosome 3 in uncultured renal cell carcinomas by interphase cytogenetics

PURPOSE: Analysis of genetic alterations may facilitate the differential diagnosis of renal cell carcinoma (RCC) subtypes. For genetic classification, deletion of the short arm of chromosome 3 (3p), the hallmark of nonpapillary/clear cell RCC, is a major diagnostic criterion. Because of the limited routine applicability of cytogenetics and molecular genetic techniques we investigated interphase fluorescence in situ hybridization (FISH) for the detection of this aberration in RCC. MATERIALS AND METHODS: Using seven chromosome 3 specific probes FISH was performed on isolated nuclei from 26 uncultured sporadic RCC. RESULTS: Alterations of chromosome 3 were identified in 19 RCC (73%). Monosomy and/or 3p-deletions were observed in 15 of 19 (79%) non-papillary/clear cell RCC but not in other morphologic subgroups. The median percentage of cells in a specimen containing loss of 3p was 45%. Deletion mapping indicated that large deletions affecting different regions in 3p are predominant. Chromosomal region 3p24 was recurrently involved in all RCC with a deletion in 3p. CONCLUSION: Interphase FISH for the detection of loss in 3p provides a sensitive and feasible method for the genetic classification of kidney tumors and the delineation of recurrently deleted regions in 3p.     

The role of the B cell receptor V region in peripheral B cell survival

We investigate the role of the antigen-specific B cell receptor (BCR) in the establishment and maintenance of the peripheral B cell pools. We studied the fate of a population of transgenic B cells expressing a BCR without V region (Tg(deltaVmu)). We found that the Tg(deltaVmu) B cells can populate the peripheral B cell pools in the absence of other B cells, but when in the presence of a second population of non-transgenic B cells, they are virtually absent from the mature B cell compartments. By studying the rate of accumulation of 5-bromo-2'-deoxyuridine we show that the peripheral Tg(deltaVmu) B cells have a shorter life-span compared to non-transgenic B cells. By directly comparing the fate of two populations of transgenic B cells, either lacking or expressing a V region, we were able to assign the poorest competitive ability and the short peripheral survival of the Tg(delatVmu) B cells to the lack of an antigen-binding site. The results obtained support the involvement of the V region in the persistence of peripheral B cell populations.     

Prevalence, morphology and biology of renal cell carcinoma in von Hippel-Lindau disease compared to sporadic renal cell carcinoma

PURPOSE: Renal cell carcinoma occurs as a sporadic tumor but may be part of the autosomal dominant von Hippel-Lindau disease, characterized by retinal and central nervous system hemangioblastoma, pheochromocytoma, pancreatic cysts and renal cell carcinoma. We determine the prevalence of von Hippel-Lindau disease in a series of unselected renal cell carcinoma cases by molecular genetic analysis, and compare sporadic to von Hippel-Lindau renal cell carcinoma with respect to morphology and biology. MATERIALS AND METHODS: We established registers comprising 63 subjects with von Hippel-Lindau renal cell carcinoma, belonging to 30 distinct families (register A), and 460 unselected patients operated on for renal cell carcinoma in an 11-year period (register B). Molecular genetic analysis of the von Hippel-Lindau gene was performed for living patients of register A, representing 80% of von Hippel-Lindau families, and register B, 62% living patients, to identify von Hippel-Lindau germline mutations. In addition, register B was evaluated by a questionnaire (95% response) for familial occurrence of von Hippel-Lindau disease. RESULTS: The prevalence of von Hippel-Lindau renal cell carcinoma was 1.6% in 189 consenting unselected renal cell carcinoma patients. Risk factors for occult germline von Hippel-Lindau gene mutations in register B included familial renal cell carcinoma in 3 of 3 patients (100%), multifocal or bilateral renal cell carcinoma in 1 of 10 (10%) and age younger than 50 years at diagnosis in 1 of 33 (3%). Compared to sporadic von Hippel-Lindau renal cell carcinoma was characterized by an occurrence 25 years earlier, association with renal cysts, multifocal and bilateral tumors, cystic organization and low grade histology, and a better 10-year survival (p < 0.001 each). In von Hippel-Lindau disease metastases occurred only in tumors larger than 7 cm. CONCLUSIONS: von Hippel-Lindau differs from sporadic renal cell carcinoma in morphology and biology. Our data provide arguments for planning surgery for von Hippel-Lindau renal cell carcinoma and should stimulate future investigations.     

Immunoreactivity for LN2 and LN3 distinguishes small cell carcinomas from non-small cell carcinomas in the lung

The hydrolyzing activities of O-hexyl O-2,5-dichlorophenyl phosphoramidate (HDCP) and p-nitrophenyl butyrate (p-NPB) in chicken serum had been found to copurify in the same protein, identified as albumin. The hydrolyzing activities of both chicken serum and commercial serum albumins from different species were inhibited in a dose-dependent manner by short chain fatty acids. On simultaneous incubation of chicken serum with HDCP and p-NPB, a competitive interaction was detected between the two substrates. This behavior suggests that both are hydrolyzed in the same albumin active site. When chicken serum was preincubated with one of the substrates, and the latter were withdrawn by large dilution, the hydrolyzing activities with both substrates were found to be reduced. This reduction was in turn dependent upon the time of preincubation with the first substrate. These results suggest that HDCP and p-NPB are hydrolyzed by the same albumin active site, via a mechanism based on transient phosphorylation/acylation of the active site. The proposed hydrolysis mechanism would account for the hydrolytic kinetics of both substrates.     

Allele-specific late replication and fragility of the most active common fragile site, FRA3B

FRA3B at 3p14.2 is the most active of the common fragile sites in the human genome and is expressed when cells are exposed to the DNA replication inhibitor, aphidicolin. Several lines of evidence suggest that fragile sites are regions of late replication. To elucidate the relationship between the timing of replication across the FRA3B region and its corresponding fragility, we labeled cells with 5-bromo-2'-deoxyuridine (BrdU) and adopted an immunofluorescent procedure to visualize late replicating DNA (BrdU-substituted DNA) in metaphase chromosomes. We also chose 21 markers along the FRA3B region and analyzed the timing of replication using BrdU-labeled DNA from different stages of the cell cycle sorted by flow cytometry. Our results show that there are two distinct alleles that replicate at different stages in the cell cycle and that breaks/gaps preferentially occurred on the chromosome 3 with the late replication allele. These results provide direct evidence that allele-specific late replication is involved in the fragility of the most active common fragile site, FRA3B.     

Absence or reduction of Fhit expression in most clear cell renal carcinomas

The FHIT gene at human chromosome region 3p14.2 straddles the common fragile site, FRA3B, and numerous homozygous deletions in cancer cell lines and primary tumors. Also, the 3p14.2 chromosome breakpoint of the familial clear cell kidney carcinoma-associated translocation, t(3;8)(p14.2;q24), disrupts one FHIT allele between exons 3 and 4, fulfilling one criterion for a familial tumor suppressor gene: that one allele is constitutionally inactivated. Because the FHIT gene sustains biallelic intragenic deletions rather than mutations, there has not been evidence that the FHIT gene frequently plays a role in kidney cancer, although replacement of Fhit expression in a Fhit-negative renal carcinoma cell line suppressed tumor growth in nude mice. We have now assessed 41 clear cell renal carcinomas for expression of Fhit by immunohistochemistry. Normal renal tubule epithelial cells express Fhit uniformly and strongly, whereas 51% of the tumors are completely negative, 34% of tumors show a mixture of positive and negative cells, and 14% are uniformly positive, although usually less strongly positive than the normal epithelial cells. Most interestingly, there was a correlation between complete absence of Fhit and the G1 morphological grade and early clinical stage. Morphological grades G2 and G3 exhibited a mixture of positive and negative cells with a tendency for a higher fraction of negative cells in G3. Fhit inactivation is likely to be an early event in G1 tumors and may be associated with progression in G2 and G3 tumors.     

Basal cell carcinomas of the auricular region: a study of 23 cases

Basal cell carcinomas (BCCs) of the auricular region are not frequently reported, especially in the Japanese literature. Predisposing conditions such as sun exposure or frostbite are possibly involved in their development. In this study, we report our cases of auricular BCCs, discussing the obtained results, the possible significance of predisposing conditions, and the correlation with the histologic subtypes involved. Among 1094 patients with BCCs, auricular tumors were observed in 23 patients (2.1%), 4 women and 19 men. All of them were present on the external sun-exposed auricular side. Histologic patterns were nodular and micronodular (13 cases) and infiltrative (10 cases). No differences were observed between sexes. The relative degree of elastosis was higher in men than in women. Frostbite was recorded in 4 cases. The ear is an anatomical region that is heavily exposed to sun-light and equally prone to frostbite. Our data showed that all the lesions were located on the auricular region more or less exposed to sunlight. There was a recorded previous history of predisposing factors in most cases, and the high degree of elastosis suggests the involvement of these predisposing factors. Moreover, the high prevalence of infiltrative subtypes observed in our survey suggests a possible correlation between some histologic subtypes, sun-exposure, and frostbite. The differences between the relatively high number of auricular BCCs reported in the literature in contrast with the Japanese observations suggest the involvement of social or local conditions.     

Evidence for association between renal cell carcinomas and renal cystic diseases: nationwide survey in Japan

The crucial issues in a policy debate are often matters of perception and interpretation rather than fact, and the values and norms that influence perceptions are central to an understanding of conflict in the policy arena. For example, science's norms of objectivity and disinterestedness are being modified today to accommodate closer academic-industry ties. The author traces in detail how these ties and the accompanying public distrust have developed, beginning with the post-World-War-II increase in public support for basic research and continuing with subsequent pieces of legislation that lowered the barriers between academic and industrial research in order to reap economic benefits. He then analyzes the impact of financial incentives in university-industry relationships on science and on public perceptions of science, and the price both science and the public would pay if the public loses trust in science and refuses to support it. He also reviews the history of the ill-fated National Institutes of Health guidelines for university-industry collaborations proposed in 1979 and the subsequent history of the policy on this topic recently adopted by the Public Health Service. He maintains that the PHS policy poses both a risk (the temptation to enforce the policy loosely) and an opportunity (for research institutions to grasp the initiative and develop meaningful conflict-of-interest guidelines of their own). But the policy falls short of responding to the much broader range of concerns associated with university-industry research collaboration, for example, the possible effects of such collaboration on the traditional openness and sharing among scientists. The available data on these effects are mixed. He concludes by maintaining that scientists and their industry partners should address the issues surrounding their collaboration now rather than waiting for negative events to trigger public arousal and force a mutually unsatisfying political solution. This article is one of three in this issue of Academic Medicine that deal with issues of conflict of interest in university-industry research relationships. These articles are discussed in an overview that precedes them.     

Differentiation of renal cell carcinomas from angiomyolipomas by ultrasonic frequency dependent attenuation

PURPOSE: We determined the usefulness of ultrasonic frequency dependent attenuation in differentiating hyperechoic renal cell carcinoma from angiomyolipoma. MATERIALS AND METHODS: Frequency dependent attenuation values were determined in 29 renal cell carcinomas and 13 angiomyolipomas. RESULTS: Frequency dependent attenuation values were significantly lower in renal cell carcinomas than in angiomyolipomas (0.42 versus 0.76 dB./cm./MHz.). Two of the renal cell carcinomas were as hyperechoic as the angiomyolipomas but they were clearly differentiated by the low frequency dependent attenuation. Two other renal cell carcinomas exhibited high values because of the abundance of fibrous tissue. However, they were readily diagnosed by the typical low echoic B-mode images. Frequency dependent attenuation did not differ between histological types of renal cell carcinoma. One angiomyolipoma that was poor in fat and rich in muscle components had an exceptionally low frequency dependent attenuation. Therefore, frequency dependent attenuation values can be regarded as an inversion of computerized tomography numbers. CONCLUSIONS: Frequency dependent attenuation measurement is a promising diagnostic aid in differentiating hyperechoic renal cell carcinomas from angiomyolipomas.     

A high-resolution map in the chromosomal region surrounding the Lps locus

The Lps locus on mouse chromosome 4 controls host responsiveness to lipopolysaccharide, a major component of the outer membrane of Gram-negative bacteria. The C3H/HeJ inbred mouse strain is characterized by a mutant Lps allel (Lpsd) that renders it hyporesponsive to LPS and naturally tolerant of its lethal effects. To identify the Lps gene by a positional cloning strategy, we have generated a high-resolution linkage map of the chromosomal region surrounding this locus. We have analyzed a total of 1604 backcross mice from a preexisting interspecific backcross panel of 259 (Mus spretus x C57BL/6J)F1 x C57BL/6J and two novel panels of 597 (DBA/2J x C3H/HeJ)F1 x C3H/HeJ and 748 (C57BL/6J x C3H/HeJ)F1 x C3H/HeJ segregating at Lps. A total of 50 DNA markers have been mapped in a 11.8-cM span overlapping the Lps locus. This positions the Lps locus within a 1.1-cM interval, flanked proximally by a large cluster of markers, including three know genes (Cd301, Hxb, and Ambp), and distally by two microsatellite markers (D4Mit7/D4Mit178). The localization of the Lps locus is several centimorgans proximal to that previously assigned.     

Frequent allelic losses on chromosome 13q in human male breast carcinomas

Loss of genetic material on chromosomes 13q and 17 has been suggested to be of importance in the initiation and progression of female breast cancer, but their involvement is less well illustrated in male breast carcinomas. The present study was designed to investigate the incidence of allelic loss and microsatellite instability for chromosomes 13q, 17p and 17q in 13 sporadic male breast carcinomas using matched normal-tumour DNA samples and seven polymorphic microsatellite markers. Genetic imbalance was found in one or more informative markers in 85% of the patients, with more frequent loss of heterozygosity and microsatellite instability at loci on chromosome 13q. Thus, a high incidence of allelic losses was observed at the retinoblastoma gene (4/6) and likewise at the D13S263 locus (7/12), which also exhibited the highest frequency of microsatellite instability. The intragenic microsatellite in intron 1 of the TP53 gene on chromosome 17p revealed loss of heterozygosity in 3 of 8 informative patients. The investigated proximal region of chromosome 13q is postulated to harbour several potential tumour suppressor genes associated with female breast cancer. The high incidence of allelic losses at the D13S263 microsatellite, located distal to both the BRCA2 and the Brush-1 loci but proximal to the retinoblastoma gene, possibly indicates the presence of an additional tumour suppressor gene which may be involved in male breast carcinomas. However, this hypothesis needs verification in an extended study of male breast carcinomas.     

Frequent expression of Bcl-2 in renal-cell carcinomas carrying wild-type p53

Lunate excision alone is seldom utilized in the management of Kienbock's disease due to concerns about progressive carpal collapse following removal of this central carpal bone. We report a 32-year follow-up of a patient who underwent lunate excision only for treatment of Kienbock's disease with a successful outcome. Although lunate excision is thought to be associated with a high failure rate, a review of the literature suggests that success rates following lunate excision are comparable to those reported for other more conventional techniques such as radial shortening, ulnar lengthening, limited carpal fusions, and proximal row carpectomy. The current perception that lunate excision is associated with a high failure rate is not supported in the literature. As such, it may not be appropriate to assign this operation to the category of "historical interest only."     

Frequent progesterone receptor immunoreactivity in tuberous sclerosis-associated renal angiomyolipomas

Angiomyolipomas can occur sporadically or in association with tuberous sclerosis complex (TSC). TSC is an autosomal dominant disorder characterized by seizures, mental retardation, and benign tumors of the brain, heart, kidney, and skin. Angiomyolipomas are more common in women than in men, suggesting a possible hormonal influence on tumor growth. In this study, 35 angiomyolipomas from 23 patients were immunostained with antibodies to estrogen receptor (ER) and progesterone receptor (PR). Eleven angiomyolipomas (31%) contained clusters of PR-immunoreactive smooth muscle cells. None contained ER-immunoreactive cells. Of the 21 tumors from patients with TSC, 11 (48%) were PR immunoreactive. All of the PR-immunoreactive angiomyolipomas were from women younger than 50 years of age, and all except one of these women had TSC. This study suggests that hormonal factors play a role in the pathogenesis of TSC-associated angiomyolipomas.