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Biomedical subjects

T S Frank

Publications and source records attributed to T S Frank.

At least 37 records · Page 2Linked to original sources
PubMed1998

Frequency of germline and somatic BRCA1 mutations in ovarian cancer.

Germline mutations in the BRCA1 tumor suppressor gene are thought to be the most common cause of hereditary ovarian cancer. The aim of this study was to explore further the role of BRCA1 alterations in the development of ovarian cancers. We sought to determine whether somatic BRCA1 mutations are ever present in ovarian cancers and whether mutation is always accompanied by loss of the wild-type allele. The entire coding region and intronic splice sites of BRCA1 were sequenced using genomic DNA samples from 103 unselected ovarian cancers. Thirteen clearly deleterious BRCA1 mutations and two variants of uncertain significance were found. Blood DNA was available in all but two cases and demonstrated that 4 of 13 mutations and both variants of uncertain significance were germline alterations, whereas in seven cases the mutation was a somatic change present only in the cancer. Using four microsatellite markers, loss of heterozygosity at the BRCA1 locus was found in all 15 ovarian cancers with BRCA1 sequence alterations, compared with only 58% of ovarian cancers that did not have BRCA1 mutations. BRCA1-associated ovarian cancers were characterized by serous histology and moderate histological grade. These data confirm prior reports suggesting that germline mutations in BRCA1 are present in about 5% of women with ovarian cancer. In addition, somatic mutations in BRCA1 occur in the development of some sporadic cases. The finding that both germline and somatic BRCA1 mutations are accompanied by loss of heterozygosity, suggests that loss of this tumor suppressor gene is a critical event in the development of these cancers.

Adult↗
PubMed1997

A region of interstitial 17q25 allelic loss in ovarian tumors coincides with a defined region of loss in breast tumors.

Chromosomal regions of allelic imbalance in tumors are predicted to define the general location of tumor suppressor genes. We previously localized a putative breast tumor suppressor gene to a 3 cM region on 17q25 by deletion mapping of microsatellite markers in breast tumors. To determine if the same 17q25 region of loss is important in the genesis of other tumor types, 32 ovarian tumors and 24 prostate tumors, as well as 33 additional breast tumors, were analysed with 17q25 polymorphic microsatellite markers. While no significant loss was observed in prostate tumors, greater than half of ovarian tumors exhibited loss coincident with the candidate region previously defined in breast tumors. These results suggest that one or more novel tumor suppressor genes exist on 17q25 within a concordant region of interstitial loss defined in both breast and ovarian neoplasms.

Breast Neoplasms↗
PubMed1997

Mini-microabscess syndrome in liver transplant recipients.

Cytomegalovirus (CMV) is a significant cause of morbidity in immunosuppressed patients. It is characterized in the liver by parenchymal microabscesses, usually containing CMV-infected cells. However, not all hepatic microabscesses are due to CMV infection. In 1992, we described "mini" microabscess (MMA) syndrome, a distinct clinical syndrome that occurs in transplanted livers. This report analyzes the clinical and laboratory features of 57 cases of MMA syndrome occurring in 52 patients and compares these with 19 biopsy-proven cases of CMV infection. The diagnosis of MMA syndrome can only be made histologically. The microabscesses are smaller and more numerous than in CMV infection, and there are no viral inclusions present. CMV DNA could not be detected in liver biopsy specimens with MMAs by using "nested" polymerase chain reaction (PCR), indicating that MMA syndrome is not caused by CMV infection. The pattern of liver enzyme and bilirubin elevation is predominantly hepatocellular, with transaminase levels elevated, on average, six to eight times the upper limit of normal. The clinical features of MMA syndrome are that it predominantly affects female (40 of 52 patients) orthotopic liver transplant (OLT) recipients of all ages (range, 11 months to 66.9 years). MMA syndrome is unrelated to the indication for initial OLT and tends to occur later after transplantation than CMV infection (median, 91 days post-OLT vs. 32 days for CMV hepatitis). Although the etiology of MMA syndrome is not clear, it does not appear to adversely affect graft or patient survival.

Adolescent↗
PubMed1997

Low proportion of BRCA1 and BRCA2 mutations in Finnish breast cancer families: evidence for additional susceptibility genes.

One hundred breast and breast-ovarian cancer families identified at the Helsinki University Central Hospital in southern Finland and previously screened for mutations in the BRCA2 gene were now analyzed for mutations in the BRCA1 gene. The coding region and splice boundaries of BRCA1 were analyzed by protein truncation test (PTT) and heteroduplex analysis (HA)/SSCP in all 100 families, and 70 were also screened by direct sequencing. Contrary to expectations based on Finnish population history and strong founder effects in several monogenic diseases in Finland, a wide spectrum of BRCA1 and BRCA2 mutations was found. In the BRCA1 gene, 10 different protein truncating mutations were found each in one family. Six of these are novel Finnish mutations and four have been previously found in other European populations. Six different BRCA2 mutations were found in 11 families. Altogether only 21% of the breast cancer families were accounted for by mutations in these two genes. Linkage to both chromosome 17q21 (BRCA1) and 13q12 (BRCA2) was also excluded in a subset of seven mutation-negative families with four or more cases of breast or ovarian cancer. These data indicate that additional breast and breast-ovarian cancer susceptibility genes are likely to be important in Finland.

Adult↗
PubMed1997

Detection of human papillomavirus DNA in keratoacanthomas by polymerase chain reaction.

The etiology of keratoacanthomas is unknown, but human papillomavirus (HPV) has been suspected to be involved in the pathogenesis of this lesion because koilocytic changes may be observed and because HPV has been found in cutaneous squamous-cell carcinomas and premalignant keratoses in immunosuppressed patients. We analyzed DNA extracted from 39 keratoacanthomas from 22 "at-risk" patients (nine patients undergoing UV light and/or anthralin therapy for psoriasis, 10 solid organ transplant recipients, one patient with xeroderma pigmentosa, one patient with acquired immunodeficiency syndrome, and one patient undergoing therapy for non-Hodgkin's lymphoma) for the presence of HPV. The results were compared with analyses of DNA extracted from 30 keratoacanthomas from 28 patients at no known increased risk for these lesions. Using polymerase chain reaction (PCR) primers designed to detect multiple HPV types (including 6, 11, 16, 18, 31, and 33), HPV was detected in seven keratoacanthomas from six of the at-risk patients and in eight sporadic keratoacanthomas from eight patients without risk factors. HPV was also present in one of 26 nonlesional skin controls. Statistical analysis showed a significant difference in the prevalence of HPV DNA sequences found in keratoacanthomas compared to normal control skin (p = 0.038). The presence of virus by PCR could not be predicted by histologic evaluation. Sequence analysis showed the presence of HPV types 11, 13, 24, 33, and 57. Although these results confirm the frequent presence of HPV in keratoacanthomas, the role of this virus in the etiology and pathogenesis of these lesions remains to be elucidated.

DNA, Viral↗
PubMed1997

Detection of hepatitis C by RT-PCR in formalin-fixed paraffin-embedded tissue from liver transplant patients.

The histopathologic alterations of hepatitis C virus (HCV) infection of the liver overlap with those of other diseases, making interpretation of liver biopsy specimens in some cases insufficient to render a diagnosis. Although HCV infection can be confirmed by detection of circulating anti-HCV antibodies, immunocompromised liver transplant recipients are often unable to mount an immunologic response to the virus, resulting in false-negative serologic testing. We describe the comparison of reverse transcription-polymerase chain reaction (RT-PCR) with histopathology, serology, and immunohistochemistry for the diagnosis of HCV. Sixty-three formalin-fixed, paraffin-embedded tissue samples (40 needle biopsy specimens and 23 native liver resection specimens) from 35 transplant patients were analyzed by use of a novel method of RNA extraction followed by nested PCR for HCV as well as albumin mRNA as an internal control. HCV was detected by RT-PCR in 50 of 51 (98%) paraffin sections of liver from transplant patients with circulating anti-HCV antibodies, 15 of which lacked characteristic histologic features of HCV infection. Overall, there were no false-negative results in 36 needle biopsy specimens from patients with hepatitis C infection, but three negative results were seen in end-stage cirrhotic native livers resected from HCV-infected patients. No false-positive test results were seen among 21 negative controls (10 liver samples from immunocompetent patients with abnormalities unrelated to hepatitis C and 11 liver biopsies from immunocompetent patients without histologic evidence of liver disease). In comparison, immunohistochemistry using antibody TORDJI-22 was positive for HCV in only 15 of 32 (47%) needle biopsies positive by RT-PCR. Our results indicate that RT-PCR is a more sensitive and specific method of detecting hepatitis C in routinely processed paraffin sections of formalin-fixed liver biopsy specimens than histopathologic examination or immunohistochemistry.

Formaldehyde↗
PubMed1997

Molecular analysis in endometrial cancer.

The molecular events that occur during the development of endometrial carcinoma are largely uncharacterized. Carcinomas of the endometrium are associated as extracolonic malignant tumors in patients with hereditary nonpolyposis colorectal cancer syndrome. Endometrium and ovary may develop histologically homologue cancers especially endometrioid and papillary serous carcinomas. Colon and ovarian carcinoma might serve as model systems for the molecular analysis in endometrial carcinoma. We sought to analyze in endometrial carcinoma frequent molecular mechanisms of colon and ovarian carcinoma, including Ki-ras codon 12 mutations, microsatellite instability, p53 and c-erb B-2 immunohistochemical expression and allelic loss on chromosome 17q. Our results indicate that molecular mechanisms in endometrial carcinoma are different than those responsible for colorectal carcinomas and that uterine papillary serous carcinomas shares with its ovarian counterpart several molecular alterations in contrast to the histologically homologue uterine and ovarian endometrioid carcinoma. Furthermore there is a molecular basis to distinguish uterine endometrioid and papillary serous carcinoma.

Chromosome Deletion↗
PubMed1996

Detailed deletion analysis of sporadic breast tumors defines an interstitial region of allelic loss on 17q25.

Whole genome analyses of breast tumors with polymorphic markers have detected nonrandom loss of heterozygosity on multiple chromosomes, providing clues to the locations of suspected tumor suppressor genes. Tumors are thought to initiate, progress, and metastasize as mutations accumulate in multiple growth-regulatory genes; thus, identification and characterization of these genes are critical to understanding and controlling breast tumorigenesis. To map more precisely a novel breast tumor suppressor gene that has been localized previously to distal 17q, we constructed a detailed deletion map of 17q25 by analyzing eight microsatellite markers on 39 sporadic primary breast tumors. The smallest overlapping region of interstitial loss was narrowed to approximately 3 cM and included D17S937/AFM107ye3, which showed the highest percentage of allelic loss (41%). These results provide a framework from which a genomic contig will be constructed and candidate transcripts will be analyzed.

Alleles↗
PubMed1996

Analysis of chronic endometritis for Chlamydia trachomatis by polymerase chain reaction.

Chronic endometritis is characterized histologically by plasma cells infiltrating endometrial stroma. Although it has been speculated that many instances of chronic endometritis are infectious, the origin of most cases is not apparent by routine histopathologic evaluation. Chlamydia trachomatis, an obligate intracellular bacterium, is known to cause chronic endometritis in the setting of pelvic inflammatory disease. The authors analyzed 43 specimens of histopathologically diagnosed chronic endometritis from 38 patients for C trachomatis by PCR using primers for the single-copy major outer membrane protein (MOMP) gene. C trachomatis was detected in only one such case in which dense plasma cell infiltrates were present and concurrent C trachomatis infection of the cervix was documented. Using serially diluted DNA from formalin-fixed, paraffin-embedded McCoy cells, the sensitivity of this method was shown to be equivalent to a single infected cell in a paraffin section. In conjunction with the results of other studies, these data indicate a limited role, if any, of C trachomatis in the origin of mild or moderate chronic endometritis.

Adolescent↗
PubMed1996

Histologic progression of recurrent hepatitis C in liver transplant allografts.

The incidence and severity of recurrent hepatitis C virus (HCV) infection in liver transplant recipients vary widely, and the long-term sequelae of recurrent infection are not known. To better define the biology of recurrent HCV in liver transplant patients, we reviewed the histology of recurrent HCV in serial biopsies of 19 patients with pretransplant polymerase chain reaction (PCR) evidence of HCV infection. All posttransplant (post-TX) biopsies (n = 81) were reviewed, and RNA was extracted from at least one paraffin-embedded biopsy from each patient. RNA was analyzed for HCV by nested, reverse transcription-PCR (RT-PCR) using primers for the 5' non-coding region of HCV as well as for albumin (as an internal control). All post-TX biopsies tested (12-1,677 days post-TX) were positive for HCV RNA by RT-PCR, while normal control biopsies were negative. Fifteen of 19 patients developed recurrent chronic hepatitis typical of HCV. Many of these patients showed a progression from early biopsies with acute lobular hepatitis to later biopsies with chronic hepatitis with portal lymphoid aggregates. An acute lobular hepatitis typified by sinusoidal lymphocytosis, acidophil bodies, and lobular disarray was seen an average of 135 days post-TX, with a range of 39-279 days. The time post-TX between this and earlier non-hepatitis biopsies was significantly different (p < 0.0004, Student's t test). Chronic hepatitis with portal lymphoid aggregates was seen an average of 356 days post-TX, with a range of 89-1,365 days. The time post-TX was significantly longer than for acute lobular hepatitis (p < 0.03, Student's t test). Fifty-three percent of HCV TX patients progressed from acute lobular hepatitis to chronic hepatitis with lymphoid aggregates within 1 year of TX, and 79% showed these changes within 4 years. Six patients had progressive fibrosis; one die of liver failure and two became cirrhotic. Recurrent HCV appears to progress from an acute lobular hepatitis to chronic hepatitis with lymphoid aggregates in the majority of patients. Significant scarring occurred in 32% of patients and 16% developed end-stage liver disease from recurrent HCV. These later findings suggest that the long-term course of recurrent HCV in liver allografts may not be as indolent as first thought.

Base Sequence↗
PubMed1996

Comparison of methods for extracting DNA from formalin-fixed paraffin sections for nonisotopic PCR.

DNA was extracted from unstained 5-microns sections of neutral buffered 10% formalin-fixed paraffin-embedded tissue by proteinase K digestion without detergents followed by boiling, proteinase K digestion with ionic detergents with and without phenol chloroform extraction and ethanol precipitation, sonication with proteinase K followed by boiling, or boiling alone. Serial 1:10 dilutions of the extracted DNA were subject to polymerase chain reaction (PCR) amplification of a 255-bp portion of the p53 gene. Digestion with proteinase K without ionic detergents followed by boiling (without phenol chloroform extraction) gave the best yield, enabling visualization of ethidium bromide-stained PCR product from a DNA dilution corresponding to 0.1 mm2 of tissue containing of the order of 10(3) nuclear profiles. Proteinase K digestion with detergents followed by phenol-chloroform extraction was no more effective than simple boiling. Although the success of PCR from preserved tissue will vary with the fixative and size of the amplified fragment, DNA extracted with this optimized method can be used for identification of viruses, loss of heterozygosity, and immunoglobulin gene rearrangements in paraffin-embedded tissue without radioisotopes.

Base Sequence↗
PubMed1996

Clinical and pathological significance of microsatellite instability in sporadic endometrial carcinoma.

Defective DNA mismatch repair in neoplasia is manifested by extra, aberrant bands within multiple microsatellite markers. The replication error (RER) phenotype is present in most colorectal and endometrial carcinomas in patients with the hereditary nonpolyposis colorectal carcinoma syndrome. In addition, a minority of sporadic colorectal and endometrial carcinomas are RER positive. RER in sporadic colorectal carcinomas has been associated with improved prognosis, but its clinical significance in sporadic endometrial cancer has not been characterized. We analyzed DNA extracted from 109 formalin-fixed sporadic endometrial carcinomas for microsatellite instability. The RER-positive phenotype was demonstrated by microsatellite instability in more than one of the eight dinucleotide markers tested. RER was correlated with pathological and clinical parameters as well as with immunohistochemical staining for the p53 gene product and alterations in codon 12 of Ki-ras. Nine percent of the endometrial carcinomas were RER positive, and RER was significantly associated with high grade and adverse outcome. We found no significant correlation of RER with histological subtype, stage, depth of invasion, mutations in the 12th codon of Ki-ras, or p53 immunoreactivity. We conclude that the RER phenotype is present in a minority of sporadic endometrial carcinomas and is associated with high grade and poor prognosis.

Adult↗
PubMed1996

Analysis of paraffin sections of Crohn's disease for Mycobacterium paratuberculosis using polymerase chain reaction.

Although Mycobacterium paratuberculosis has been reported by both culture and polymerase chain reaction in unfixed intestinal tissue from patients with Crohn's disease, its pathologic significance is unclear. We used polymerase chain reaction to analyze DNA for the presence of M. paratuberculosis from 27 specimens in 23 patients with Crohn's disease. Seventeen of these cases contained granulomata. DNA from unstained paraffin tissue sections was amplified using nested PCR specific for a 264-base pair fragment of IS900, a multicopy insertion element specific to M. paratuberculosis. The sensitivity of this technique was demonstrated by the amplification of small numbers of cultured organisms in a paraffin cell block in the presence of large amounts of added human DNA. M. paratuberculosis was not identified in any of the specimens from patients with Crohn's disease, nor in any of 11 normal colon sections tested. Therefore, we were unable to confirm a role for M. paratuberculosis in Crohn's disease.

Crohn Disease↗
PubMed1995

Somatic mutations in the BRCA1 gene in sporadic ovarian tumours.

The BRCA1 gene on chromosome 17q21 is responsible for an autosomal dominant syndrome of increased susceptibility to breast and ovarian cancer but no somatic mutations in tumours have yet been described. To study the potential role of BRCA1 in sporadic carcinogenesis, we analysed the genomic DNA of tumour and normal fractions of 47 ovarian cancers for mutations in BRCA1 using the single-strand conformation polymorphism technique. We now describe somatic mutations in the DNA of four tumours which also had loss of heterozygosity (LOH) at a BRCA1 intragenic marker. Our data support a tumour suppressor mechanism for BRCA1; somatic mutations and LOH may result in inactivation of BRCA1 in at least a small number of ovarian cancers.

Adolescent↗
PubMed1995

Epstein-Barr virus coinfection and recombination in non-human immunodeficiency virus-associated oral hairy leukoplakia.

Human immunodeficiency virus-associated oral hairy leukoplakia (HLP) is characterized by coinfection with multiple types and strains of Epstein-Barr virus (EBV) and recombination within the EBV genome. HIV-seronegative immunosuppressed and immunocompetent patients with HLP were examined to determine the pathogenic contribution of EBV coinfection and recombination to the development of HLP. Multiple coinfecting EBV strains were detected in both HLP specimens and peripheral blood lymphocytes (PBL) of HIV-seronegative persons with HLP. One specific EBV strain was detected in HLP specimens from 3 of 4 patients. Also, viral recombination during productive replication within HLP generated variants of the latent membrane protein-1 (LMP-1) and nuclear antigen-2 (EBNA-2) genes. Some variants were also detected within PBL. Thus, EBV coinfection and recombination are consistent findings in persons with HLP regardless of immune status. Virally mediated determinants may be important features of EBV pathogenesis.

Adult↗
PubMed1995

Mutations of the Ki-ras oncogene in carcinoma of the endometrium.

Mutations of the Ki-ras oncogene in endometrial carcinoma have been reported in Japan, but the prevalence and clinical significance of such mutations in the United States remains unclear. DNA extracted from paraffin sections of 112 carcinomas of the endometrium was amplified by the polymerase chain reaction with mismatched primers that generated a BstNI recognition site with the wild-type codon 12. Loss of this recognition site indicating Ki-ras codon 12 mutations was observed in 13 tumors (11.6%), including 11 endometrioid carcinomas, one undifferentiated carcinoma, and one carcinosarcoma. None of 17 papillary serous-clear cell carcinomas contained Ki-ras codon 12 mutations. These mutations were confirmed and characterized by direct sequencing. We found no evidence of correlation of the presence of Ki-ras mutations with stage, grade, depth of invasion, or clinical outcome. Our results indicate that Ki-ras oncogene mutations in carcinoma of the endometrium may be less prevalent in the United States than in Japan.

Adenocarcinoma↗