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V V Murty

Publications and source records attributed to V V Murty.

At least 73 records · Page 4Linked to original sources
PubMed1991

Detection and analysis of origin of i(12p), a diagnostic marker of human male germ cell tumors, by fluorescence in situ hybridization.

The i(12p) chromosome marker has been shown to be a diagnostic and prognostic marker of human male germ cell tumors (GCTs). An analysis of the i(12p) and chromosome 12 aneuploidy was performed in five primary cell cultures and three established cell lines derived from human male GCTs by fluorescence in situ hybridization (FISH) with a chromosome 12 centromere-specific alpha-satellite DNA probe. Distinct differences in the centromeric signals originating from the i(12p) and normal chromosome 12 were detected, which were found to be useful for unambiguous distinction between the i(12p) and normal chromosomes 12 at interphase as well as at metaphase in these cultures. This method can be used for rapid screening of large numbers of interphase cells, eliminating the main limitation of conventional karyotypic analysis, namely, frequent inability to obtain sufficient numbers of dividing cells in direct preparations or in short-term culture of fresh biopsies. Our analysis of chromosome 12 centromeric signal size along with karyotypic data and results of analysis of restriction fragment length polymorphisms (RFLPs) on 12q in four GCTs suggested that the i(12p)s are formed by nonreciprocal centromeric interchanges between nonsister chromatids of homologous chromosomes.

Aneuploidy↗
PubMed1990

Nonrandom chromosome abnormalities in testicular and ovarian germ cell tumor cell lines.

We report the karyotypic analysis of seven testicular and one ovarian germ cell tumor (GCT) cell lines, a number of which have previously been partially investigated. An i(12p) was found in each of the testicular GCT cell lines, while it was absent in the ovarian GCT cell line. Thus, our study extends to cell lines the observation from fresh tumor tissues that i(12p) is a highly nonrandom chromosomal abnormality of testicular GCT. Additional consistent nonrandom abnormalities in the testicular GCT cell lines included the following: del(1)(p22), del(1)(q21), i(1q), del(7)(q11.2), and del(12)(q14). The del(12)(q14) abnormality was identified in five of the cell lines investigated. This observation, together with previous detection of this marker chromosome in fresh tumor specimens by us and others, suggests that loss of genetic material on 12q may represent a primary change associated with malignant transformation of testicular germ cells. As reported in a previous study, a t(15;20)(p11;q11) translocation was identified in the ovarian GCT cell line. Interestingly, it also was seen in one testicular GCT cell line. In addition, a der(15)t(15;20)(p11;q11) marker chromosome was identified in two other testicular GCT cell lines. Thus, this reinvestigation of GCT cell lines has resolved the discrepancy regarding the occurrence of i(12p) in fresh tumors versus established cell lines and identified additional nonrandom abnormalities of potential importance to the development of GCTs.

Cell Line↗
PubMed1990

Detection of preferential NRAS mutations in human male germ cell tumors by the polymerase chain reaction.

We have studied 31 male germ cell tumors (GCTs) for probable mutations in codons 12, 13, and 61 of HRAS, KRAS, and NRAS oncogenes using the polymerase chain reaction. Twenty of the thirty-one tumors exhibited NRAS gene mutations, 14 in codon 61, and six in codon 12, whereas no mutations were detected in HRAS and KRAS genes. The NRAS mutations were equally prevalent in seminomatous and nonseminomatous GCTs. Thus 13 of 22 seminomas, six of seven embryonal carcinomas, and one of two mixed tumors exhibited mutations. Two non-seminomatous tumors (an embryonal carcinoma and a yolk sac/teratoma) had mutations in both codons 12 and 61. The high frequency of NRAS mutations observed in the present study suggests that NRAS gene products may play an important role in growth regulatory functions of premalignant and malignant germ cells.

DNA Mutational Analysis↗
PubMed1990

Cytogenetic and molecular analysis of human male germ cell tumors: chromosome 12 abnormalities and gene amplification.

We report karyotypic analysis of 24 male germ cell tumors (GCTs) with clonally abnormal karyotypes biopsied from testicular and extragonadal lesions from 20 patients belonging to the histologic categories seminoma, teratoma, embryonal carcinoma, choriocarcinoma, and endodermal sinus tumor. Chromosomes 1, 7, 9, 12, 17, 21, 22, and the X chromosome were nonrandomly gained in these tumors. Nonrandom structural changes affected most frequently chromosomes 1 and 12, the latter as i(12p) and/or del(12)(q13----q22). The i(12p) was seen in 90% of tumors which included all histologic subtypes and gonadal as well as extragonadal presentation. Our present results, along with those from published data on fresh GCT biopsies, establish that i(12p) is a highly nonrandom chromosome marker of all histologic as well as anatomic presentations of GCTs. in contrast, we found del(12)(q13----q22) exclusively in nonseminomatous GCTs (NSGCTs) and mixed GCTs (MGCTs) occurring in 44% of such lesions. Because successful cytogenetic analysis of fresh tumor specimens is not always possible, we developed a method based on DNA analysis to detect i(12p) as increased copy number of 12p. In addition to the changes affecting chromosome 12 identified above, we have detected, for the first time, cytological evidence of gene amplification in the form of homogeneously staining regions (HSRs) and double minute chromosomes (dmins) in treated as well as untreated primary extragonadal and metastatic GCTs and confirmed the presence of amplified DNA in one of these tumors at the molecular level by the in-gel renaturation method. Hybridization of DNA from cultured cells from an HSR-bearing tumor with a panel of probes for genes known to be amplified or otherwise perturbed in diverse tumor systems did not identify the amplified gene, suggesting amplification of a novel gene or genes. This study comprises the largest series of GCT cytogenetics attempted so far. Notably, it includes data on a series of primary mediastinal tumors, a group which previously has not been studied in any detail.

Blotting, Southern↗
PubMed1990

Isochromosome 12p in non-seminoma cell lines: karyologic amplification of c-ki-ras2 without point-mutational activation.

We examined eight human germ cell cancer lines (GCCLs) for cytogenetic abnormalities and found an isochromosome 12p, i(12p), marker in all seven male nonseminoma GCCLs, but not in the single female teratocarcinoma cell line. Southern blot analysis of these cell lines showed increased copy number for c-ki-ras2, a gene located on 12p, in all the male GCCLs. The comparison of Southern blot analysis for a restriction fragment length polymorphism (RFLP) probe localized to 12p to a probe for int-1, which maps to 12q, indicates that the increased copy number for c-ki-ras2 is primarily from the greater numbers of 12p relative to 12q. Although Northern analysis revealed enhanced mRNA expression for c-ki-ras2 in the GCCLs with an i(12p), hybridization of specific end-labelled oligonucleotides to the polymerase chain reaction products of c-ki-ras2 codons 12, 13, or 61 did not identify c-ki-ras2 mutations of these codons in these cells. Thus, c-ki-ras2 activation through point mutation is an infrequent event in GCCLs. These data further suggest that increased 12p copy number is a common event in the transformation process leading to male germ cell cancer. We conclude that determination of 12p copy number by cytogenetic analysis or Southern blotting is useful in the diagnostic evaluation of human germ cell cancer.

Blotting, Southern↗
PubMed1988

Chromosomal phenotypes in patients with precancerous lesions of the uterine cervix progressed to cancer during follow-up.

A cytogenetical analysis of chromosomal aberrations, sister chromatid exchanges (SCEs), C-band heteromorphisms and nucleolar organizer regions was done in lymphocytes of 30 patients with precancerous lesions of the uterine cervix progressed to carcinoma and of 30 patients with nonprogressed lesions in a period of 60 months follow-up, in order to identify if any differences existed between low-risk and high-risk dysplasias. Increased frequency of chromosomal breaks, SCEs and C-band heteromorphisms of chromosome 1 and decreased activity of ribosomal genes was observed in patients with dysplasias progressed to carcinoma compared to that of nonprogressed precancerous lesions. The present study thus suggests an intimate relationship between the constitutional chromosomal phenotypes and development of cancer, and these may serve as useful biological markers in defining dysplasias at high risk to progress to cancer.

Adult↗
PubMed1987

Abnormalities at chromosome region 3p12-14 characterize clear cell renal carcinoma.

In an effort to determine whether or not any characteristic chromosomal abnormalities exist in renal cancer, cytogenetic findings were correlated with tumor histology in nine cases of renal adenocarcinoma. Metaphase preparations adequate for analysis were obtained from cultures harvested between day 3 and day 21. Model chromosome number was diploid in three cases, hypodiploid in three, and hyperdiploid in the remaining three. One clear cell adenocarcinoma failed to reveal any chromosomal abnormality. Two tumors, a tubular/papillary carcinoma and an acinar/papillary carcinoma, showed the clonal abnormalities del(1)(p2l),+2,+7,+8,+12,+13,+16,+17,-21 and t(2;10)(q14-21;q26),+7q,+11q,-18, respectively. Interestingly, five of six clear cell tumors studied had clonal abnormalities affecting the short arm of chromosome #3 in the 3p12-21 region, and in the remaining case, of 15 karyotyped metaphases suitable for interpretation, one showed a deletion in 3p. These data indicate that clear cell carcinoma of the kidney may be associated with a nonrandom chromosomal abnormality involving the 3p12-14 region.

Adult↗
PubMed1987

Heteromorphisms of C-bands in patients with precancerous and cancerous lesions of the cervix uteri.

C-band heteromorphisms of chromosomes 1, 9 and 16 were studied in 62 patients with cervical cancer, 100 women with various grades of precancerous lesions and 47 normal women as controls. The data showed an increased frequency of heteromorphisms of chromosome 1 in patients with cancer (48.39%) and severe dysplasias (40%) as compared to controls (29.8%) and lower grades of dysplastic lesions, i.e. mild and moderate (28.8%). The increase in the incidence of chromosome 1 heteromorphisms in cancer was found to be statistically significant (p less than 0.05) compared to controls. The present study indicates that C-band heteromorphisms may play some role in the development of malignancy of the uterine cervix.

Chromosome Aberrations↗
PubMed1987

Mitomycin C induced chromosomal aberrations and sister chromatid exchanges (SCEs) in lymphocytes of patients with precancerous and cancerous lesions of the uterine cervix.

Baseline and mitomycin C (MMC)-induced chromosomal aberrations and sister chromatid exchanges (SCEs) in blood lymphocytes of patients with cervical precancerous and cancerous lesions and normal women were studied. The baseline frequency of chromosomal aberrations and SCEs revealed a significant increase in higher grades of precancerous (moderate and severe dysplasias) and cancerous lesions compared to those of controls. The MMC-induced chromosomal aberrations and SCEs did not show any differential response in the different groups studied. The results thus indicate that chromosomal instability as observed in precancerous and cancerous lesions is not associated with their sensitivity to mitomycin C.

Chromosome Aberrations↗
PubMed1986

Extracellular matrix-modulated expression of human cell surface glycoproteins A42 and J143. Intrinsic and extrinsic signals determine antigenic phenotype.

We have used serologic, biochemical, and genetic methods to characterize two stage-specific human differentiation antigens of neural and melanocytic cells: A42 (57,000 Mr glycoprotein) and J143 (140,000/30,000 Mr glycoprotein). The genes determining A42 and J143 cell surface expression in rodent-human hybrids were chromosomally mapped, and the respective human chromosomes were introduced into rodent cells derived from distinct differentiation lineages. Serologic analysis of the resulting hybrid clones has permitted the identification of two types of regulatory signals determining A42 and J143 expression. First, both antigens are expressed in hybrids constructed with antigen-positive human cells and also in certain hybrids constructed with antigen-negative human cells, indicating that intrinsic signals provided by the differentiation program of the rodent fusion partner induce antigen expression. Second, a series of human-mouse neuroblastoma hybrids, which are A42- or J143- when cultured on plastic surfaces, can be induced to express the antigens when cultured on substrates coated with extracellular matrix (ECM) produced by bovine corneal endothelial cells or fibronectin. This induction of antigen expression by extrinsic, ECM-derived signals is accompanied in the neuroblastoma hybrids by increased substrate adhesiveness and cell spreading and by characteristic changes in cell morphology. A similar program of phenotypic changes is also seen in spontaneous variants of human neuroblastoma and Ewing's sarcoma cells and in ECM-induced Ewing's sarcoma cells. These findings suggest that ECM-derived signals have a role analogous to mitogens and soluble differentiation factors in modulating differentiation phenotypes and tissue-specific patterns of cell surface antigen expression.

Antibodies, Monoclonal↗
PubMed1986

Sister chromatid exchanges in patients with precancerous and cancerous lesions of cervix uteri.

The frequency of sister chromatid exchanges (SCEs) was studied in leucocytes from 46 patients with cervical carcinoma, 89 precancerous lesions, and 43 age-matched control women. The frequency of SCEs was found to be 10.15 +/- 2.49 in cancer, 8.83 +/- 2.15 in precancerous lesions, and 7.55 +/- 2.24 in controls. The analyses of SCE data revealed a highly significant (P less than 0.001) increase in precancerous and cancerous lesions compared to controls. The intra-chromosomal distribution of SCEs revealed a random increase in various chromosomal groups in patients with cancer and dysplasia compared to controls. The mean SCE level among various groups of precancerous lesions according to severity of pathological condition did not show significant differences. However, 70.8% of dysplasia cases revealed SCE levels higher than the average in controls. The increased frequencies of SCEs in the majority of cancer patients and a few precancerous lesions indicate that individuals with high SCE levels may be at a high risk of developing cancer. Thus the usefulness of SCE levels as a preclinical marker to identify the high risk group of dysplasias needs to be ascertained by follow-up studies; these are in progress.

Adult↗
PubMed1986

Physical mapping of the factor VIII gene proximal to two polymorphic DNA probes in human chromosome band Xq28: implications for factor VIII gene segregation analysis.

Genomic DNA segments for the coagulation factor VIIIc gene (F8C), which exhibits only limited restriction length polymorphism, map to the proximal region of band Xq28 by somatic cell hybridization analysis and in situ hybridization. Using somatic cell hybrids, we have obtained data which place probes DX13 (used to detect locus DXS15) and St14 (used to detect DXS52) distal to F8C, within band Xq28. Previous studies have mapped the factor IX gene (F9) and probe 52A (used to detect DXS51) proximal to F8C, in Xq26----q27 and Xq27, respectively (Camerino et al., 1984; Drayna et al., 1984; Mattei et al., 1985). Thus, the relative order of genetic marker loci in the Xq27----qter region is most likely cen-F9-DXS51-F8C-(DXS15, DXS52)-Xqter. The collection of these molecular probes is thus potentially useful in three-factor crosses of factor VIII gene segregation.

Animals↗
PubMed1986

The cellular homologue of the transforming gene of SKV avian retrovirus maps to human chromosome region 1q22----q24.

We report the chromosomal localization of the cellular oncogene SKI, the putative oncogene of the Sloan-Kettering viruses (SKVs), a group of transforming retroviruses that had been isolated from chicken embryo cells infected with the avian leukosis virus tdB77. Southern blot analysis of DNA from mouse X human somatic cell hybrids with the v-SKI probe established synteny with chromosome 1, but excluding the region 1pter----q21. In situ hybridization of the same probe both to human spermatocyte pachytene and lymphocyte metaphase chromosomes enabled precise localization of the gene to the region 1q22----q24, a region that frequently is involved in translocations and other rearrangements in diverse human tumor types. In situ hybridization studies of metaphase spreads from a small noncleaved cell lymphoma that exhibited a t(1;14)(q21;q32) translocation showed that SKI translocates to the der(14) chromosome. Cytogenetic analysis of 65 prospectively ascertained non-Hodgkin's lymphomas revealed that the SKI region undergoes nonrandom breakage leading to translocations. Further analysis of the chromosome breaks in this group of lymphomas suggested that those involving the SKI site probably are of importance in tumor progression.

Animals↗
PubMed1985

Nucleolar organizer regions in patients with precancerous and cancerous lesions of the uterine cervix.

Nucleolar organizer regions (Ag-NORs) were studied in patients with cervical precancerous and cancerous lesions along with controls. The data revealed a statistically significant decrease of Ag-NORs in cancer patients, as well as in women with severe precancerous lesions as compared with controls. A similar decrease in the amount of Ag-staining was also observed in both cancer and severe dysplasia cases. The study suggests a possible relationship of Ag-NOR activity to malignancy.

Adult↗