Molecular cloning of the interleukin-1 beta converting enzyme.

Interleukin-1 beta (IL-1 beta) mediates a wide range of immune and inflammatory responses. The active cytokine is generated by proteolytic cleavage of an inactive precursor. A complementary DNA encoding a protease that carries out this cleavage has been cloned. Recombinant expression in COS-7 cells enabled the cells to process precursor IL-1 beta to the mature form. Sequence analysis indicated that the enzyme itself may undergo proteolytic processing. The gene encoding the protease was mapped to chromosomal band 11q23, a site frequently involved in rearrangement in human cancers.

The human gene encoding phosphatidylinositol-3 kinase associated p85 alpha is at chromosome region 5q12-13.

The human chromosomal location of the gene encoding the phosphatidylinositol-3 kinase associated protein, p85 alpha, has been determined by analysis of its segregation in rodent-human hybrids and by chromosome in situ hybridization using a complementary DNA clone, GRB-1. The gene for p85 alpha is at chromosome region 5q13, perhaps near the gene encoding another receptor associated signal transducing protein, the GTPase activating protein.

Detailed genetic and physical map of the 3p chromosome region surrounding the familial renal cell carcinoma chromosome translocation, t(3;8)(p14.2;q24.1).

Extensive studies of loss of heterozygosity of 3p markers in renal cell carcinomas (RCCs) have established that there are at least three regions critical in kidney tumorigenesis, one most likely coincident with the von Hippel-Lindau gene at 3p25.3, one in 3p21 which may also be critical in small cell lung carcinomas, and one in 3p13-p14.2, a region which includes the 3p chromosome translocation break of familial RCC with the t(3;8)(p14.2;q24.1) translocation. A panel of rodent-human hybrids carrying portions of 3p, including a hybrid carrying the derivative 8 (der(8)(8pter-->8q24.1::3p14.2-->3pter)) from the RCC family, have been characterized using 3p anchor probes and cytogenetic methods. This 3p panel was then used to map a large number of genetically mapped probes into seven physical intervals between 3p12 and 3pter defined by the hybrid panel. Markers have been physically, and some genetically, placed relative to the t(3;8) break, such that positional cloning of the break is feasible.

B-raf and a B-raf pseudogene are located on 7q in man.

The B-raf gene was localized to human chromosome region 7p11-7qter by Southern blot analysis of its segregation in a panel of rodent-human hybrids, using a B-raf cDNA clone. Chromosomal in situ hybridization refined the localization to 7q33-36. Analysis of genomic B-raf clones identified a B-raf pseudogene in addition to the active gene. Based on the chromosomal mapping data we conclude that the pseudogene is located near the active gene.

The FHIT gene is alternatively spliced in normal kidney and renal cell carcinoma.

FHIT (Fragile Histidine Triad), a putative tumor suppressor gene, was cloned from fetal brain and colon cDNA libraries. Portions of this gene are deleted in esophageal, colon, lung and breast tumors, but this gene has not been found altered in sporadic renal cell carcinomas. We report here an alternatively spliced form of this gene cloned from a kidney cDNA library. This cDNA is 1189 bp in length, and contains an additional 94 bp exon, designated exon 2a (E2a). This novel sequence is located between exon 2 and exon 3 of the FHIT gene's untranslated region and exon 2a is present in all normal kidney tissues and cell lines. Analyses performed on sporadic renal cell carcinoma (RCC) tissues and cell lines, show consistent loss of exon 8 of the FHIT cDNA in almost 60% of the cases. Interestingly, in a familial, as well as, in a metastatic RCC, derived from a patient with the sporadic form, exon 2a and exon 3 are also deleted. Northern analyses with the exon 2a of the familial and the metastatic RCC demonstrates concurrent loss of expression of a 4.4 kb transcript with the loss of the E2a sequence, suggesting that exon 2a of the FHIT gene may play an important role in the oncogenesis of renal cell carcinoma.

A rearranged transforming gene, tre, is made up of human sequences derived from chromosome regions 5q, 17q and 18q.

The transfection recombinant transforming gene, tre, originated from discontinuous human genetic elements after transfection of NIH3T3 cells with genomic DNA from a Ewing's sarcoma cell line. Probes for the three normally discontinuous human elements involved in the transfection recombinant were subcloned and used in conjunction with a panel of rodent-human hybrid cells to determine their normal location in the human genome. The leftmost (5') element derives from the long arm of chromosome 5 (5q); the internal fragment derives from human chromosome 18 proximal to the bcl-2 gene; and the rightmost (3') element derives from the long arm of chromosome 17 (17q) distal to an acute leukemia breakpoint at 17q21. In situ hybridization of the same probes to human metaphase chromosomes confirmed localization of these sequences to regions 5q23----q31, 18q12, and 17q12----q22.

A novel transcriptional unit of the tre oncogene widely expressed in human cancer cells.

Tre is a recombinant gene isolated from NIH3T3 cells transfected with human Ewing's sarcoma DNA. It is composed of three major genetic elements derived, 5' to 3', from human chromosomes 5, 18 and 17. We report here on transcripts from the 3' domain of tre. The transcripts were cloned from a cDNA library of cytoplasmic poly(A)+ RNA from tre-transfected NIH3T3 tumor cells. The complete cDNA sequence, 8201 nucleotides, possessed an unusually long non-coding region and a translatable region with two open reading frames. In one cDNA clone, the presence of two insertions suggested the possibility of alternative splicing. The sequence mapped to the centromere-proximal region of 17q. Transfection-tumorigenicity assays with the open reading frames subcloned into expression vectors were positive for the reading frame adjacent to the 5' non-coding region and negative for the second, downstream, reading frame and the possible alternatively spliced versions of both reading frames. Analysis of the 786 amino acid sequence deduced from the 5' reading frame predicted a highly hydrophilic protein with two charge clusters suggesting nucleic acid-binding properties. When used as probe, the cloned sequence detected RNA transcripts in a wide variety of human cancer cells regardless of their lineage of origin from different tissues, but not in human cells from normal tissue.

Identical clonal origin of synchronous and metachronous low-grade, noninvasive papillary transitional cell carcinomas of the urinary tract.

One of the most important biological features of papillary transitional cell carcinoma (pTCC) of the urinary tract is its multicentricity and its tendency for recurrences. Two possible mechanisms, field effect and intramucosal seeding/spreading, have been proposed. The former theory hypothesizes that carcinogenic agents cause synchronous or metachronous malignant transformation of multiple urothelial cells (independent clonal origin), and the latter speculates that synchronous and metachronous tumors are derived from implantation or direct spreading of tumor cells (identical clonal origin). We tested these hypotheses by analyzing the methylation patterns of the androgen receptor gene (HUMARA) located at the X-chromosome. Thirty-five metachronous and synchronous, low-grade (grade 1 or 2), noninvasive pTCCs of the urinary tract from 10 heterozygous female patients were successfully analyzed using formalin-fixed, paraffin-embedded tissue. These included 16 recurrent bladder tumors from 4 patients, 10 metachronous bladder and ureter/renal pelvis tumors from 4 patients, and 9 multifocal tumors from 2 patients. All tumors are monoclonal as indicated by unbalanced methylation of HUMARA. Furthermore, same methylated allele was detected in multiple recurrent or multifocal tumors from any given patient, indicating their identical clonal origin. We conclude that low-grade, noninvasive pTCCs are monoclonal in nature. Synchronous or metachronous pTCCs have an identical clonal origin, strongly supporting the intramucosal seeding/spreading hypothesis.

Atypical endometrial hyperplasia shares genomic abnormalities with endometrioid carcinoma by comparative genomic hybridization.

Endometrial hyperplasia is a common disorder that is now observed with increasing frequency in women treated with hormonal replacement therapy or with tamoxifen. This study was undertaken to determine whether genomic features of various forms of endometrial hyperplasias would allow their classification as a benign, premalignant, or malignant abnormality. Comparative genomic hybridization (CGH) was performed on endometrial glands microdissected by laser capture microscope from 19 archival endometrial samples, comprising 5 normal endometria, 1 polyp, 2 simple hyperplasias, 5 hyperplasias with nuclear abnormalities (atypical hyperplasias), and 4 low-grade and 2 high-grade endometrioid carcinomas, 1 with squamous component (adenoacanthoma). Genomic DNA, extracted from the glands and the squamous component in 1 case, was amplified by degenerate oligonucleotide-primed polymerase chain reaction (DOP-PCR) and compared with sex-matched DNA by CGH. No genomic imbalances were observed in the normal samples, the polyp, or the simple hyperplasias. However, in atypical hyperplasia, regardless of the level of cytologic atypia, genomic abnormalities were observed that also occurred in endometrioid carcinomas. Chromosomes 1, 8, and 10 were most often affected. The results are compared with molecular genetic abnormalities recently reported in these lesions. This study strongly suggests that atypical endometrial hyperplasias are closely related to endometrioid carcinoma and should be considered precancerous lesions, contrary to simple hyperplasia, which is a benign disorder. The squamous component of one of the high-grade carcinomas showed genetic abnormalities similar to those of endometrioid carcinoma and therefore does not represent squamous metaplasia but is an integral part of the malignant process.

Gene mapping in cancer.

Observation of genetic alterations that appear consistently in specific types and stages of cancer provides a strong impetus to cancer geneticists to focus their investigations on the exploration of such volatile regions of the human genome. Introduction of powerful molecular cytogenetic and molecular genetic methods in recent years permits more detailed analysis, which will help researchers in their efforts to determine if such areas of the human genome have a functional role in the initiation and progressive development of leukemias and solid tumors. This discussion will focus on several provocative molecular cytogenetic tools that are currently available to localize potential cancer-associated genes and on how these methods are being used in conjunction with the current modes of analysis, including cytogenetics and somatic cell genetics. In addition, we will explore how these methods will help to isolate and dissect recently discovered cancer-associated genes within the human genome. All of these methods used in combination with each other will provide essential DNA markers for future diagnostic and prognostic evaluation of cancer.

Clonal chromosome aberrations with monosomy of chromosome 8 in a case of grade III chondrosarcoma.

We report cytogenetic findings in a case of grade III chondrosarcoma. Complex clonal chromosome aberrations including monosomy of chromosomes 4, 8, 13, and a consistent t(5;14)(q23;p12) were observed in all cells. There were no structural or numerical anomalies involving chromosome 12. The complexity of the chromosome aberrations reflect the advanced stage of this chondrosarcoma; we suggest a possible involvement of the EXT1 gene located on chromosome 8.

Regional chromosome localization of human papillomavirus integration sites near fragile sites, oncogenes, and cancer chromosome breakpoints.

The integration sites of human papillomavirus (HPV) DNA within the cervical carcinoma cell line C4-I and a primary cervical tumor were mapped by in situ hybridization. Cloned cellular sequences flanking the integrated viral DNA were used as probes. For the cell line, the viral integration site was mapped to chromosome region 8q21-q22.3, while in the primary tumor chromosome band 3p21 was the target for integration. The HPV DNA integration appears to occur in the vicinity of fragile sites, oncogenes, and chromosome breakpoints that are characteristic of hematologic malignancies and solid tumors. The integration of HPV may thus promote chromosome changes in cancer cells.

The breakpoint in 22q11 in a case of Ph-positive acute lymphocytic leukemia interrupts the immunoglobulin light chain gene cluster.

With a constant region probe (c-lambda) from the immunoglobulin light chain gene cluster, we performed in situ hybridization to bone marrow chromosome preparations from a patient with a Ph-positive form of acute lymphocytic leukemia. Results in this patient indicate that the immunoglobulin chain genes were involved in the 9;22 chromosome rearrangement.

Characterization of t(11;19)(q23;p13.3) by fluorescence in situ hybridization analysis in a pediatric patient with therapy-related acute myelogenous leukemia.

This case presents a Caucasian girl diagnosed with early pre-B cell acute lymphoblastic leukemia at age 2 years. The only chromosomal anomaly detected in her bone marrow cells at this time was an add(12p). By age 4 years, she had a bone marrow and central nervous system (CNS) relapse of ALL and was treated with chemotherapy that included etoposide. She was in complete remission for 2 years following chemotherapy with etoposide, but later developed therapy-related acute myeloid leukemia (t-AML). At this time, a t(11;19)(q23;p13.3) rearrangement was detected in her bone marrow cells. The AML relapsed again 1 year after allogeneic bone marrow transplant (BMT). The presence of a chromosome 11 abnormality involving band 11q23 in this patient suggests that the transformation from ALL to t-AML was a consequence of etoposide included in her chemotherapy. Studies have shown that the 11q23 breakpoint in the t(11;19) rearrangement is consistent, and involves the MLL gene in t-AML patients. However, the breakpoint in 19p is variable in that it could be located either at 19p13.1 or 19p13.3 and thus could involve either of two genes: ELL (11-19 lysine-rich leukemia gene) on 19p13.1 or ENL (11-19 leukemia gene) on 19p13.3. In this study, the t(11;19)(q23;p13.3) was further characterized and the breakpoint regions were defined by fluorescence in situ hybridization (FISH) analysis.

Cytogenetic findings in primary uveal melanoma.

We analyzed cytogenetic abnormalities in 10 cases of primary uveal melanoma. Clonal chromosomal abnormalities were present in nine cases. Chromosome 6 was most commonly affected (seven cases) and included gain of material from 6 and/or loss of material from 6q. Trisomy of chromosome 8 or gain in material from 8q, mostly in the form of an i(8q) resulting in three to five copies of the 8q segment was seen in six cases. Monosomy of chromosome 3 and rearrangements of chromosome 9 were less frequent and were altered in three cases each. Clinical, histopathologic, and cytogenetic abnormalities are correlated.

Cytogenetics of small cell carcinoma of the lung.

Nineteen cell lines derived from various malignant tissues of 15 patients with small cell carcinoma of the lung (SCCL) have been studied. The results showed heterogeneity in all cell lines, with no one consistent abnormality among them. Cell lines from 11 of the patients had minute and double minute chromosomes, and cell lines from 2 patients had abnormally banding regions, designated as ABRs, as distinguished from homogeneously staining regions (HSRs). The latter 2 and several of the former cell lines were derived from specimens taken before the patients were placed on therapy. All but 2 of the cell lines had a constant marker load, consisting of 24%-35% of the complement. Some markers remained stable through months and years of culture life, while other markers came and went. Chromosomes #1, #6 and #11 were most frequently involved in marker formation in the cell lines, and these were compared to similar markers in direct bone marrow preparations. Chromosome #1 markers were of variable structure, whereas #6 and #11 most often took the form of 6q- and 11p+ markers, with breakpoints most frequently at 6q23-25 and 11p11-12. A 3p- marker was found in a minority of cell lines. All of these markers were also found in direct marrow preparations from some patients with SCCL. Nonmonoclonal tumors arose from inoculation of bimodal cell lines into nude mice, but population selection by undetermined mechanism was evident. Cytogenetic parameters showed no positive correlation with hormone production by these cell lines.

Chromosome microdissection: a brief overview.

Chromosome microdissection arose as a means of facilitating long range physical mapping of chromosome regions involved in either a genetic or malignant disorder. However, with the rapid development of improved techniques for mapping and sequencing the human genome, microdissection is considered by many investigators to be a cumbersome and time consuming procedure. Nonetheless, based on the impressive number of informative diagnostic DNA markers that are now available as a result of this technology, microdissection still must be considered one of the most rapid and direct methods available for generating new DNA markers from any chromosome region, irrespective of its sequence composition. In addition, it remains an important means to dissect DNA markers from any organism, eukaryotic and prokaryotic, and has resulted in generating disease associated DNA sequences from both human and animal genomes. Recently, microdissection of single cells has emerged as a viable alternative for isolating pure populations of specific cell types, especially tumor cells, which can then be studied without background contamination from any other cellular constituents. This overview will provide a glimpse into the present applications of the microdissection technology, as well as the importance this technology will have for future exploration into the human genome.

In situ hybridization and translocation breakpoint mapping. III. DiGeorge syndrome with partial monosomy of chromosome 22.

We have performed in situ hybridization of a probe for the lambda IGLC constant region to metaphase spreads from two DiGeorge syndrome (DGS)-related chromosomal rearrangements with breakpoints in 22q11. In this study we have demonstrated that the breakpoints are proximal to the lambda IGLC constant region cluster. Thus, at the molecular level, DGS-related breakpoints can be distinguished from the 22q11 breakpoint of CML, but not from the 8;22 translocation of Burkitt lymphoma or from the 21;22 translocations that we have previously studied.

Gene for incontinentia pigmenti maps to band Xp11 with an (X;10) (p11;q22) translocation.

Incontinentia pigmenti (IP) is a genetic disease that is usually lethal in males. We report finding an X;10 translocation in a girl with IP. Three other X/autosome translocations have been observed in females with IP: two involving chromosome 9 and one involving chromosome 17. The breakpoint in all four cases in the X chromosome was in band Xp11. The IP gene locus can therefore be confidently assigned to the X chromosome and, specifically, to band Xp11. The IP gene is most likely to subband Xp11.2. We propose that IP may prove to be a submicroscopic deletion.