Frozen-thawed rhinoceros sperm exhibit DNA damage shortly after thawing when assessed by the sperm chromatin dispersion assay

This study reports on the successful validation (via in situ nick translation and neutral comet assay) of the equine Sperm-Halomax kit as an appropriate methodology for the assessment of sperm DNA fragmentation in three species of rhinoceros. Rhinoceros sperm nuclei with fragmented DNA (validated using in situ nick translation) were evident as large halos with dispersed DNA fragments, whereas those with nonfragmented DNA displayed small halos of nondispersed DNA within the microgel. There was a high correlation (r) of 0.974 (R(2) value=0.949; P<0.01; n=16) between the respective assessments of the Sperm Chromatin Dispersion test (SCDt) and the neutral comet assay. Application of the SCDt to determine the DNA fragmentation dynamics of rhinoceros (n=6) sperm frozen in liquid nitrogen vapor and incubated postthaw at 37 degrees C for up to 48 h to mimic in vitro conditions in the female reproductive tract, revealed an increase (P=0.001) in DNA damage, as soon as 4h after the start of incubation. Linear regression equations were calculated for all six rhinoceroses over the first 6h of incubation and revealed individual animal variation. Freshly collected and incubated (37 degrees C) rhinoceros (n=3) sperm had no increase in the basal level of DNA fragmentation for up to 48 h, indicating that the cryopreservation of rhinoceros sperm in liquid nitrogen vapor, as used in this study, appeared to result in freeze-thaw DNA damage.

A lepidopteran orthologue of reaper reveals functional conservation and evolution of IAP antagonists

Genetic studies in Drosophila melanogaster have revealed that inhibitor of apoptosis (IAP) proteins and IAP antagonists such as reaper play a pivotal role in controlling cell death in insects. Interestingly, although the sequences and structures of IAPs are highly conserved, the sequence of IAP antagonists diverged very rapidly during evolution, making their identification difficult. Using a customized bioinformatics approach, we identified an IAP antagonist, IAP-binding motif 1 (Ibm1), from the genome of the silkworm Bombyx mori. This is the first reaper/grim orthologue identified in a nondipteran insect. Previous analysis indicated that both Reaper and Grim induce cell death through their N-terminal IBM as well as the Grim_helix3 (GH3) domain. Functional studies indicated that Ibm1 binds to an IAP protein from B. mori, BmIAP1, and induces apoptosis in insect cells via the IAP-binding motif, a seven amino acid sequence that is highly conserved in all IAP antagonists. Interestingly, Ibm1 also contains a region that is a statistically significant match to the GH3 domain. Mutational analysis indicated that the GH3-like motif in Ibm1 has an important supportive role in IAP-antagonist function and can trigger cell death under certain conditions.

Caspase inhibitor P35 is required for the production of robust baculovirus virions in Trichoplusia ni TN-368 cells

Apoptosis can protect lepidopteran insects against baculovirus infection by limiting viral replication. Baculoviruses counter this response by expressing anti-apoptotic proteins such as the caspase inhibitor P35, which is expressed by several baculoviruses including Autographa californica mutiple nucleopolyhedrovirus (AcMNPV). Mutants of AcMNPV that lack the p35 gene induce apoptosis in Spodoptera frugiperda cells, and replication of these mutants is severely curtailed in S. frugiperda cell lines and larvae. However, cells from another lepidopteran species, Trichoplusia ni, do not undergo apoptosis when infected with AcMNPV mutants lacking p35, and p35 mutant and wild-type viruses replicate to equivalent levels in the T. ni cell line TN-368 and have equivalent infectivity in T. ni larvae by either oral or intrahaemocoelic injection. This has led to the conclusion that p35 is not required for AcMNPV replication in T. ni. However, in this study it was found that stocks of p35 mutant virus produced in TN-368 cells had defects in virion stability and infectivity. TN-368 cells infected with p35 mutant AcMNPV exhibited caspase activity, despite a lack of apoptosis, and propagation of the mutant virus in the presence of a chemical caspase inhibitor restored the normal infection phenotype to the progeny virus. These results suggest that caspases can directly or indirectly damage baculovirus virions, and reveal a novel aspect of the role of apoptosis in antiviral defence.

Human olfactory epithelial cells generated in vitro express diverse neuronal characteristics

The olfactory epithelium constitutes the sole source of regenerating neural cells that can be obtained from a living human. As such, primary cultures derived from human olfactory epithelial biopsies can be utilized to study neurobiological characteristics of individuals under different conditions and disease states. Here, using such human cultures, we report in vitro generation of cells that exhibit a complex neuronal phenotype, encompassing receptors and signaling pathways pertinent to both olfaction and other aspects of CNS function. Using in situ hybridization, we demonstrate for the first time the native expression of olfactory receptors in cultured cells derived from human olfactory epithelial tissue. We further establish the presence and function of olfactory transduction molecules in these cells using immunocytochemistry, calcium imaging and molecular methods. Western blot analysis revealed the expression of neurotransmitter receptors for dopamine (D2R), 5-HT (5HT2C) and NMDA subtypes 1 and 2A/2B. Stimulation with dopamine or 5-HT enhanced receptor G protein activation in a subtype specific manner, based on 35S-guanosine triphosphate incorporation assay. Functional characteristics of the cultured cells are demonstrated through enhanced tyrosine phosphorylation of NMDAR 2A/2B and recruitment of signaling partners in response to NMDA stimulation. The array of neuronal characteristics observed here establishes that proliferating cells derived from the human olfactory epithelium differentiate in vitro to express functional and molecular attributes of mature olfactory neurons. These cultured neural cells exhibit neurotransmitter pathways important in a number of neuropsychiatric disorders. Their ready availability from living humans thus provides a new tool to link functional and molecular features of neural cells with clinical characteristics of individual living patients.

Annotation and expression profiling of apoptosis-related genes in the yellow fever mosquito, Aedes aegypti

Apoptosis has been extensively studied in Drosophila by both biochemical and genetic approaches, but there is a lack of knowledge about the mechanisms of apoptosis regulation in other insects. In mosquitoes, apoptosis occurs during Plasmodium and arbovirus infection in the midgut, suggesting that apoptosis plays a role in mosquito innate immunity. We searched the Aedes aegypti genome for apoptosis-related genes using Drosophila and Anopheles gambiae protein sequences as queries. In this study we have identified eleven caspases, three inhibitor of apoptosis (IAP) proteins, a previously unreported IAP antagonist, and orthologs of Drosophila Ark, Dnr1, and BG4 (also called dFadd). While most of these genes have been previously annotated, we have improved the annotation of several of them, and we also report the discovery of four previously unannotated apoptosis-related genes. We examined the developmental expression profile of these genes in Ae. aegypti larvae, pupae and adults, and we also studied the function of a novel IAP antagonist, IMP. Expression of IMP in mosquito cells caused apoptosis, indicating that it is a functional pro-death protein. Further characterization of these genes will help elucidate the molecular mechanisms of apoptosis regulation in Ae. aegypti.

Polymorphisms in the VKORC1 gene are strongly associated with warfarin dosage requirements in patients receiving anticoagulation

BACKGROUND

Warfarin is a mainstay of therapy for conditions associated with an increased risk of thromboembolic events. However, the use of this common agent is fraught with complications and little is known regarding inter-individual variation in warfarin response.

OBJECTIVE

We tested for association between single nucleotide polymorphisms (SNPs) in VKORC1 and CYP2C9 and average weekly warfarin dose required to maintain patients at their desired anticoagulation target.

METHODS

The sample consisted of 93 European-American patients from anticoagulation clinics at the University of North Carolina at Chapel Hill. Data on mean weekly warfarin dose were collected over a mean treatment period of 20.6 months. ANCOVA models were used and haplotype analysis was performed.

RESULTS

Three of six VKORC1 SNPs were found to be very strongly associated with the average warfarin dose required to achieve the target international normalised ratio (INR; p<0.0001). The mean weekly dose by genotype ranged from approximately 27 to 47 mg. There was no evidence for an association between either of the two CYP2C9 polymorphisms studied, CYP2C9*2 and CYP2C9*3. CYP2C9*3 was significantly (p = 0.05) associated with average warfarin dosage after adjustment for VKORC1*1173.

CONCLUSIONS

These results are of considerable clinical interest and confirm recently published results regarding the role of these two genes in modifying warfarin metabolism and maintenance dosage. The consistent findings regarding the role of VKORC1 and CYP2C9 in warfarin metabolism and maintenance dosage represent a clinically useful proof of principal for the use of pharmacogenomic information in medicine and may lead to improved understanding of warfarin's actions.

Decreased SBPase activity alters growth and development in transgenic tobacco plants

The effects of reduced SBPase activity on growth and development were examined in a set of transgenic tobacco plants produced using an antisense construct driven by the ribulose bisphosphate carboxylase, small subunit promoter. Photosynthetic carbon assimilation rates and carbohydrate levels in source leaves were decreased in the antisense plants. Growth rate and total shoot biomass were reduced in the SBPase antisense plants, even in plants where SBPase activity was reduced by only 25%. Floral biomass also decreased in response to reductions in SBPase activity and the onset of flowering was delayed by 5-10 d. This is the first demonstration of a link between reproductive biomass and reductions in Calvin cycle enzyme activity using antisense plants. Furthermore, unexpected changes in the growth and development of the antisense plants were evident. Small reductions in SBPase activity (above 50% wild type) resulted in shorter plants with only a small decrease in stem biomass and specific leaf area. In contrast, plants with larger reductions in SBPase activity had an increase in specific leaf area and attained heights similar to that of the wild-type plants but with a much reduced stem biomass, largely due to a decrease in xylem tissue. This bi-modal response of growth to reductions in SBPase activity has similarities to changes in leaf and stem anatomy and morphology that accompany light acclimation.

Psychological consequences of road traffic accidents for children and their mothers

BACKGROUND

Little is known about the psychological and behavioural consequences of road traffic accidents for children. The study aimed to determine the outcome of road traffic accidents on children and their mothers.

METHOD

A 1-year cohort study of consecutive child attenders aged 5-16 years at an Accident and Emergency Department. Data were extracted from medical notes and from interview and self-report at baseline, 3 months and 6 months.

RESULTS

The children had an excellent physical outcome. Fifteen per cent suffered acute stress disorder; 25% suffered post-traumatic stress disorder at 3 months and 18% at 6 months. Travel anxiety was frequent. Post-traumatic consequences for mothers were common.

CONCLUSION

Psychological outcome was poor for a minority of children and associated with disability, especially for travel. There were significant family consequences. There is a need for changes in clinical care to prevent, identify and treat distressing and disabling problems.

Cognitive predictors of posttraumatic stress disorder in children: results of a prospective longitudinal study

The present study explored whether cognitive factors specified in the Ehlers and Clark model (Behav. Res. Ther. 38 (2000) 319) of posttraumatic stress disorder (PTSD) predict chronic PTSD in children who had experienced a road traffic accident. Children were assessed at 2 weeks, 3 months, and 6 months after the accident. Data-driven processing during the accident, negative interpretation of intrusive memories, alienation from other people, anger, rumination, thought suppression and persistent dissociation at initial assessment predicted PTSD symptom severity at 3 and 6 months. On the basis of sex and stressor severity variables, 14% of the variance of PTSD symptoms at 6 months could be explained. The accuracy of the prediction increased to 49% or 53% when the cognitive variables measured at initial assessment or 3 months, respectively, were taken into account.

Posttraumatic stress disorder after motor vehicle accidents: 3-year follow-up of a prospective longitudinal study

The paper presents a 3-year follow-up of a prospective longitudinal study of posttraumatic stress disorder (PTSD) after motor vehicle accidents (J. Abnormal Psychol., 107 (1998) 508). Participants were 546 patients who had been assessed when attending an emergency clinic shortly after a motor vehicle accident, and at 3 months and 1 year afterwards. The prevalence of posttraumatic stress disorder PTSD at 3 years was 11%. Maintaining psychological factors, i.e. negative interpretation of intrusions, rumination, thought suppression and anger cognitions, were important in predicting the persistence of PTSD at 3 years, as were persistent health and financial problems after the accident. Other predictors were female sex, hospital admission for injuries, perceived threat and dissociation during the accident, and litigation.

Outcome in consecutive emergency department attenders following a road traffic accident

BACKGROUND

Little is known about the consequences of road traffic accidents.

AIMS

To determine psychological and social outcome at 3 months and 1 year following a road traffic accident.

METHOD

A cohort study of a 1-year sample of consecutive attenders (n=1148) aged 17-69 years at the accident and emergency department of a teaching district general hospital (excluding major head injury). Data were extracted from medica notes and from self-report at baseline, 3 months and 1 year.

RESULTS

Most (61%) injuries were physically minor. At 1 year 45% reported major physical problems and 32% reported psychiatric consequences. Non-injury variables were the principal predictors of outcome.

CONCLUSIONS

Outcome across a range of variables is considerably worse than would be expected from the nature of the physical injuries. There is a need for changes in clinical care and socio-legal policy to prevent, identify and treat distressing and disabling chronic problems.

Prediction of psychological outcomes one year after a motor vehicle accident

OBJECTIVE

The authors' goal was to identify predictors of 1-year outcomes for consecutive patients in a hospital emergency department following motor vehicle accidents and to describe the prevalence and course of four types of psychiatric outcomes after such accidents.

METHOD

Consecutive patients aged 17-69 years who attended a general hospital emergency department following a motor vehicle accident were identified. Medical information for these patients was extracted from case notes, and the patients completed self-report questionnaires at baseline (soon after the accident), 3 months after the accident, and 1 year after the accident. Measures included a self-report scale for posttraumatic stress disorder (PTSD), the Hospital Anxiety and Depression Scale, and questions about phobic travel anxiety. Logistic regression was used to examine predictors of outcome.

RESULTS

Different frequencies and courses of PTSD, phobic travel anxiety, general anxiety, and depression were reported by a third of the subjects at both 3-month and 1-year follow-up. Many of the subjects reported improvements between 3 and 12 months, but others described late onset of psychiatric outcomes after the accident. There were differences in baseline and 3-month predictors of each type of 1-year outcome.

CONCLUSIONS

The four types of psychiatric outcomes after a motor vehicle accident that were noted overlap, are persistent, and have different early predictors. These findings have implications for the early recognition of psychiatric consequences of motor vehicle accidents that would enable early intervention.

Can clinical assessment of chest pain be made more therapeutic?

We describe the referral and management of consecutive patients attending a cardiac service with the presenting complaint of chest pain. Of 610 consecutive new referrals to five Oxford cardiac clinics over 12 weeks, 202 had chest pain as the presenting complaint: 91 (45%) angina, 101 (50%) non-cardiac chest pain, 8 (4%) both and 2 (1%) uncertain diagnosis. Information in clinic letters was sometimes ambiguous and contradictory and suggested a lack of precise information to patients. Patients with non-cardiac chest pain often had long histories, including considerable previous use of services and specialist investigations. There were delays in referral and assessment of patients. There are opportunities for simple changes in assessment procedures which might have substantial advantages for outcome and resource: (i) more detailed referral information from general practitioners, with an explicit statement of the reasons for referral; (ii) minor modifications to augment the assessment by provision of unambiguous information to patients and primary care at discharge.

Unconsciousness, amnesia and psychiatric symptoms following road traffic accident injury

BACKGROUND

Although road traffic accident injury is the most common cause of traumatic brain injury, little is known of the prevalence of psychiatric complications or the significance of unconsciousness and amnesia.

AIMS

To describe amnesia and unconsciousness following a road traffic accident and to determine whether they are associated with later psychological symptoms.

METHOD

Information was obtained from medical and ambulance records for 1441 consecutive attenders at an emergency department aged 17-69 who had been involved in a road traffic accident. A total of 1148 (80%) subjects completed a self-report questionnaire at baseline and were followed up at 3 months and 1 year.

RESULTS

Altogether, 1.5% suffered major head (and traumatic brain) injury and 21% suffered minor head injury. Post-traumatic stress disorder (PTSD) and anxiety and depression were more common at 3 months in those who had definitely been unconscious than in those who had not, but there were no differences at 1 year.

CONCLUSIONS

PTSD and other psychiatric complications are as common in those who were briefly unconscious as in those who were not.

Loss of heterozygosity in P53, BRCA1, and estrogen receptor genes and correlation to expression of p53 protein in ovarian epithelial tumors of different cell types and biological behavior

Loss of heterozygosity (LOH) of tumor suppressor genes (TSGs) in ovarian epithelial tumors of differing cell types and biological behavior has not been thoroughly investigated. Moreover, there have been conflicting reports correlating LOH of the p53 gene to overexpression of p53 protein. This study evaluated 34 formalin-fixed, paraffin-embedded ovarian epithelial tumors for LOH by polymerase chain reaction (PCR) for the following microsatellite markers: TP53(17p13.1/p53 gene), D17S579(17q/BRCA1 gene), and ESR (6q24-27/estrogen receptor gene). LOH of the TP53 marker was detected in 4 (44%) of 9 informative serous cystadenocarcinomas (SCa) but in 0 of 4 informative clear cell carcinomas (CCa) and 0 of 5 informative serous tumors of low malignant potential (SLMP). LOH of the BRCA1 marker was detected in 5 (83%) of 6 informative SCa, but in 1 (13%) of 8 informative CCa and 1 (14%) of 7 informative SLMP. LOH of the ESR marker was detected in 4 (50%) of 8 informative SCa, but in 0 of 4 informative CCa and 1 (16%) of 6 informative SLMP. p53 protein overexpression was present in 8 of 12 SCa but did not correlate to TP53 LOH. LOH for TP53, D17S579/ BRCA1, and ESR is common in ovarian SCa, and is observed in primary tumors as well as metastases. In contrast, these genetic alterations are less common in CCa and in the biologically less aggressive SLMP tumors. These data suggest different mechanisms of oncogenesis in ovarian epithelial tumors of different cell types and biological behavior.

LOH at the APC/MCC gene (5Q21) is frequent in early stages of non-small cell lung cancer

Lung cancer is the leading cause of death in both women and men in the United States and many European countries. Molecular cytogenetic and LOH analyses of non-small cell lung cancer have shown somatic genetic alterations in a variety of chromosomes, such as 1p, 3p, 5q, 8p, 9p, 11p, 11q and 17p. Allelic deletions of the known tumor suppressor gene APC at 5q21 are frequently observed in advanced stages of lung cancer and have been correlated with poor prognosis in previous reports. We investigated 33 cases of NSCL for LOH at 5q21: 22 squamous cell and 11 adenocarcinomas. Normal and tumor cells were microdissected from paraffin embedded tissues and PCR amplification was performed utilising the specific markers D5S299 and D5S346 at 5q21 and PYGM at 11q13, respectively. Clinicopathological data, survival and recurrence rates were obtained in all cases. We detected LOH at 5q21 in 4/9 (44%) informative adenocarcinomas and in 13/16 (81%) informative SCC. LOH was frequent in early stages (12/15 stage I cases) and did not correlate with recurrence or poor survival. Our results show that LOH at 5q21 is more frequent in squamous cell carcinomas than in adenocarcinomas, is frequent in early stages of the disease, and does not have prognostic significance.

The use of microsatellite instability in the distinction between synchronous endometrial and colonic adenocarcinomas

The association of endometrial carcinoma with other gynecologic neoplasms, especially ovarian and fallopian tube carcinoma, has been well documented and is usually interpreted as a result of a field defect. Sporadic synchronous primary carcinomas occurring in the endometrium and colon are extremely rare, especially in the absence of the familial genetic abnormalities seen in hereditary nonpolyposis colorectal carcinoma (HNPCC) syndrome, and may present a diagnostic dilemma. Two cases of synchronous adenocarcinomas of the endometrium and colon were studied for genetic abnormalities and differences to test for the presence of two primary tumors. Primary tumors, metastases, and normal tissues were microdissected from formalin-fixed, paraffin-embedded tissues. PCR amplification was performed for microsatellite DNA markers on chromosome 17q and 11q13. The colonic tumors were moderately and poorly differentiated, invasive, nonmucinous adenocarcinomas, whereas one uterine tumor was endometrioid adenocarcinoma and the other was papillary serous carcinoma. Although microsatellite instability, as evidenced by changes in the lengths of the amplified PCR products, was detected at 17q and 11q13 loci in the uterine and colonic neoplasms, the patterns of instability differed between the two primary tumor sites. Moreover, the lymph node metastasis in one colonic tumor had genetic alterations that differed from that of the primary tumor. In both patients, the molecular studies suggested the presence of two synchronous primary tumors. Molecular techniques may assist in distinguishing two separate primaries by determining the contraction and expansion of microsatellite regions in DNA obtained by microdissection from the primary tumors and associated metastases.

Treatment of invasive thymoma with single-agent ifosfamide

PURPOSE

To evaluate single-agent ifosfamide in the treatment of invasive thymoma.

PATIENTS AND METHODS

Fifteen patients (eight male and seven female) with histologically confirmed invasive thymoma were treated. The median age was 48 years (range, 23 to 76 years). Four patients had stage III disease, seven patients had stage IVa disease, and four patients had stage IVb disease. The most common histologic type was lymphoepithelial. Seven patients had received prior treatment, including one patient who received chemotherapy. Ifosfamide 1.5 g/m(2) was given on days 1 to 5, with mesna as a uroprotector.

RESULTS

Thirteen patients were assessable for response. Five complete responses (38.5%; 95% confidence interval [CI], 17.7% to 64.5%) and one partial response (7.7%; 95% CI, 1.4% to 33.3%) were seen. The median duration of complete response was 66+ months (range, 25 to 87 months), and the estimated survival rate 5 years after ifosfamide treatment was 57% (SE, 32% to 79%). The most frequent toxicities were nausea, vomiting, and leucopenia, but these were well tolerated.

CONCLUSION

Single-agent ifosfamide possesses significant activity against invasive thymoma and is comparable to currently used combination regimens. The inclusion of ifosfamide in combination therapy, particularly in place of cyclophosphamide in regimens such as cisplatin, doxorubicin, and cyclophosphamide, needs to be evaluated.

Leptin elimination in hyperleptinaemic peritoneal dialysis patients

BACKGROUND

Elevated plasma concentrations of leptin, a hormone thought to regulate body composition by influencing food intake/metabolic rate, are prevalent in renal failure patients. The mechanism for these increases is not known, but evidence suggests that simple accumulation due to decreased elimination is insufficient explanation.

METHODS

We studied the incidence of hyperleptinaemia in 28 end-stage renal disease patients treated with continuous ambulatory peritoneal dialysis (CAPD), compared with body-mass-index-and sex-matched controls. Results were separated by gender because women have higher leptin concentrations than men. Excretion of leptin and other substances in dialysis fluid was also studied.

RESULTS

Hyperleptinaemia was prevalent in women CAPD subjects, but not in men. Plasma leptin concentrations correlated strongly with the daily excretion of leptin in dialysis fluid. Clearance of leptin in dialysis fluid was greater in men than women CAPD subjects. Single regression analysis found that fasting insulin, glucose content of dialysis fluid, plasma albumin, C-reactive protein, erythropoietin dose, urinary creatinine clearance and plasma beta2-microglobulin were not determinants of plasma leptin concentrations. Stepwise forward multiple regression, examining the dependence of plasma leptin on body mass index, renal creatinine clearance, plasma albumin, daily dialysis fluid glucose load, daily leptin in dialysis fluid, erythropoietin dose and plasma C-reactive protein found only erythropoietin dose as a consistent negative predictor of plasma leptin concentrations.

CONCLUSIONS

The results suggest that hyperleptinaemia of CAPD was due to predisposing loss of renal elimination capacity combined with increased production due to obesity (more prevalent in women subjects of this study) and potentially female gender.

Incidence of loss of heterozygosity at p53 and BRCA1 loci in serous surface carcinoma

Serous surface carcinoma (SSC) is a neoplasm histologically indistinguishable from typical serous carcinomas that arise from the ovary but has a distinct clinical presentation. It is characterized by widespread peritoneal dissemination at presentation, but the ovaries are grossly normal in size and shape. If the carcinoma involves the ovaries microscopically, the tumor is confined to the surface or is minimally invasive. The recognition of this entity is important, because in some studies it appears to have a poorer prognosis than stage-matched serous cancers of the ovary. Loss of heterozygosity (LOH) of the p53 (17p) and BRCA1 (17q) tumor suppressor genes has been frequently identified in sporadic ovarian carcinomas. Although 17p LOH is correlated with common p53 gene mutations, inactivating mutations of the BRCA1 gene are uncommon in sporadic ovarian cases. In contrast, germline BRCA1 mutations are responsible for some hereditary forms of ovarian cancer, where it has been suggested that germline BRCA1 mutations confer a more favorable prognosis. In this study, 12 sporadic SSC were assessed for the presence of allelic deletions on the p53 and BRCA1 gene loci. DNA from both tumor and normal cells was obtained for LOH studies using tissue microdissection. Polymerase chain reaction (PCR) amplification was performed with the polymorphic DNA markers TP53 (17p13.1/p53 gene) and D17S579 (17q/BRCA1 gene). LOH in the p53 and BRCA1 loci was detected in 62.5% and 66.6% of the cases, respectively. In 50% of tumors informative for both markers, it is possible that an entire chromosome may be lost. In conclusion, we have shown that LOH of the p53 and BRCA1 loci is a frequent event in sporadic SSC, similar to what has been described in the usual form of serous ovarian carcinoma. Mutational analysis will be necessary to determine the exact role of these genes in this group of tumors.