Chromosomal localisation of the human homologues to the oncogenes erbA and B

Effects of ZnO nanoparticles on perfluorooctane sulfonate induced thyroid-disrupting on zebrafish larvae

Perfluorooctane sulfonate (PFOS) and ZnO nanoparticles (nano-ZnO) are widely distributed in the environment. However, the potential toxicity of co-exposure to PFOS and nano-ZnO remains to be fully elucidated. The test investigated the effects of co-exposure to PFOS and nano-ZnO on the hypothalamic-pituitary-thyroid (HPT) axis in zebrafish. Zebrafish embryos were exposed to a combination of PFOS (0.2, 0.4, 0.8mg/L) and nano-ZnO (50mg/L) from their early stages of life (0-14days). The whole-body content of TH and the expression of genes and proteins related to the HPT axis were analyzed. The co-exposure decreased the body length and increased the malformation rates compared with exposure to PFOS alone. Co-exposure also increased the triiodothyronine (T3) levels, whereas the thyroxine (T4) content remained unchanged. Compared with the exposure to PFOS alone, exposure to both PFOS (0.8mg/L) and nano-ZnO (50mg/L) significantly up-regulated the expression of corticotropin-releasing factor, sodium/iodidesymporter, iodothyronine deiodinases and thyroid receptors and significantly down-regulated the expression of thyroid-stimulating hormone, thyroglobulin (TG), transthyretin (TTR) and thyroid receptors. The protein expression levels of TG and TTR were also significantly down-regulated in the co-exposure groups. In addition, the expression of the thyroid peroxidase gene was unchanged in all groups. The results demonstrated that PFOS and nano-ZnO co-exposure could cause more serious thyroid-disrupting effects in zebrafish than exposure to PFOS alone. Our results also provide insight into the mechanism of disruption of the thyroid status by PFOS and nano-ZnO.

ErbB-4: a receptor tyrosine kinase

ErbB-4 is a receptor tyrosine kinase that is activated by the binding of specific growth factors to its ectodomain. In addition to the initiation of signal transduction pathways that direct cell responses, such as proliferation or differentiation, this receptor is subject to ligand-dependent trafficking events. The signal transduction events are controlled by ligand-dependent activation of the receptor tyrosine kinase activity, which results in receptor autophosphorylation and the tyrosine phosphorylation of other cellular proteins. The trafficking events include migration into and out of membrane microdomains, entry into internalization pathways and endocytosis, plus proteolytic fragmentation.

Aberrations of erbB-1 and erbB-2 oncogenes in non-dysplastic leukoplakias of the oral cavity

The purpose of this study was to analyse erbB-1 and erbB-2 oncogenes in non-dysplastic oral leukoplakia to see if we could pinpoint the first steps towards dysplasia and possible carcinogenesis. Fresh biopsy specimens of leukoplakia in 13 patients with no history of oral cancer were examined using the competitive-differential polymerase chain reaction. The mean gene copy numbers of erbB-1 and erbB-2 were calculated from the formula to compare the absolute quantities of reference gene and oncogene from 24 patients who did not have leukoplakia. Healthy mucosa was taken as controls. In eight patients with leukoplakias, the results indicated aberrations of the erbB-1 oncogene, and two patients had gene dosage changes of erbB-2. There were no signs of deletions or amplifications in the controls. These results suggest that aberrations of erbB-1 and erbB-2 are additional markers in premalignant oral lesions at the beginning of the carcinogenic process, and that genetic alterations in histologically non-dysplastic premalignant oral lesions are common.

Increased expression of epidermal growth factor receptor in normal epithelium adjacent to head and neck carcinomas independent of tobacco and alcohol abuse

OBJECTIVE

In this study we examined if expression of the epidermal growth factor receptor (EGFR) in normal epithelium adjacent to head and neck squamous cell carcinomas (HNSCC) is increased and if this increase is due to the use of tobacco and alcohol.

MATERIALS AND METHODS

Cut sections of formalin-fixed and paraffin-embedded material of histologically normal epithelium adjacent to HNSCC from 25 patients who smoke excessively and abuse alcohol, and 17 HNSCC patients who do not abuse tobacco and alcohol were compared with cut sections of normal epithelium from 27 control individuals. The sections were immunohistochemically stained for the EGFR.

RESULTS

We show an elevation of the expression of the EGFR in patients who smoke and drink excessively, that could also be ascertained, to a lesser extent, in patients that do not have a history of smoking or drinking (P = 0.08). We also find that the closer the epithelium lies to the HNSCC the higher the expression of the EGFR is.

CONCLUSIONS

Expression of the EGFR is increased in tumour-adjacent epithelium and this is not only due to the use of tobacco and/or alcohol. We suggest that paracrine effects of the HNSCC and migration of tumour cells may also play a role in this increased expression.

Numerical aberrations of chromosome 7 detected in 15 microns paraffin-embedded tissue sections of primary cutaneous melanomas by fluorescence in situ hybridization and confocal laser scanning microscopy

Fluorescence in situ hybridization (FISH) to sections of formalin-fixed paraffin-embedded archival tissues allows the detection of gene or chromosome copy number changes in interphase cell nuclei within the histological context and thus may be of particular interest in tumor pathology. In this report, we describe the application of FISH to thick (15 microns) paraffin sections of 7 primary cutaneous malignant melanomas. A chromosome 7-specific centromeric DNA probe was used to detect numerical aberrations of chromosome 7. By optical sectioning using confocal laser scanning microscopy (CLSM) only complete, uncut interphase cell nuclei were scored. The mean percentage (+/- SEM) of melanoma cell nuclei with three hybridization spots was (20.7 +/- 2.8)%; (6.8 +/- 1.0)% of nuclei showed one spot and (5.0 +/- 1.2)% four or more spots. The frequency distribution of spot numbers among melanoma cell nuclei and normal keratinocyte nuclei was significantly different (chi(2) = 176.8, df = 5, p < 0.001). Trisomy 7 was detected in all 7 cases analyzed, mostly associated with monosomy 7 or polysomy 7. The approach used in our study and the data obtained could be useful for further studies designed to investigate a possible involvement of chromosome 7 in melanocytic tumor progression.

Immunohistochemical analysis of nm23-H1 in stage I non-small cell lung cancer: a useful marker in prediction of metastases

BACKGROUND

About 30% to 40% of patients with pathologic stage I non-small cell lung cancer die within 5 years after complete resection. The identification of subgroups with high risk of recurrence is important. The level of nm23-H1/nucleoside diphosphate kinase expression has been reported to correlate inversely with the metastatic potential of some tumors.

METHODS

We examined immunohistochemically the expression of nm23-H1 in 32 stage I non-small cell lung cancers to determine its value in predicting the outcome of the operation.

RESULTS

Twelve (37.5%) recurrences and ten deaths occurred in this series. There were eight (25%) distant and four (12.5%) locoregional recurrences. Of the 32 pathologic stage I non-small cell lung cancers, 10 (31.3%) were positive for nm23-H1 gene product. None of the patients with a higher nm23-H1 protein level had detectable distant metastases at the end of this study (chi 2 test, p < 0.05). The median follow-up time to date is only 35 months (range, 18 to 83 months), and so far no significant difference in overall survival rate has been observed between the groups with high and low nm23-H1 protein levels.

CONCLUSIONS

The level of nm23-H1 protein is more useful than the T status or histologic type for the prediction of distant metastases, whereby cases may be selected for postoperative adjuvant chemotherapy.

Study on aneuploidy and p53 mutations in astrocytomas

To determine whether a correlation exists between aneuploidy and p53 status in astrocytic tumors we analyzed 48 astrocytomas with different grades of malignancy for the presence of p53 mutations and aneuploidy of chromosomes 10 and 17 (Ch10, Ch17), known to be particularly involved with this type of tumor. We used polymerase chain reaction (PCR)-based denaturing gradient gel electrophoresis (DGGE) analysis on exons 5-8 of the p53 gene, and fluorescence in situ hybridization (FISH) analysis on interphase nuclei using chromosome specific pericentromeric probes, respectively. Our results showed that Ch10/Ch17 aneuploidy is a common early event in astrocytomas (90% of low grade tumors are aneuploid). p53 mutations and Ch17 aneuploidy are early events, but their incidence is not dependent on tumor grade. Loss of Ch10 is the only alteration that significantly correlates with tumor progression. No significant correlation between the presence of Ch10/Ch17 aneuploidy and p53 mutations was found. However, the coexistence of p53 mutations and aneuploidy, was observed in a subset of cases. The presence of p53 mutations appeared to be a significant predictor of a poor prognosis. In conclusion, genomic instability may or may not be associated with p53 mutations in astrocytomas, thus suggesting that other cellular determinants can also be responsible for the aneuploidy observed.

Gene amplification in non-Hodgkin's lymphoma

Among 426 consecutively ascertained and karyotypically abnormal non-Hodgkin's lymphoma (NHL) tumours, cytological evidence for gene amplification in the form of homogeneously staining regions (HSRs) was encountered in nine cases of large cell diffuse lymphoma (LC-DL). The mean age of patients with HSRs was 62.9 years and four died within a year of diagnosis. To identify candidate gene(s) amplified in these tumours, we performed a Southern blot analysis of tumour DNA using probes for 23 known protooncogenes and the multidrug resistance gene, PGY1. Besides a two-fold amplification of the BCL2 gene in two cases, no evidence for overt amplification of any of the genes assayed was found. To confirm DNA amplification in these specimens we performed the DNA in-gel renaturation assay. Evidence for presence of amplified DNA fragments was obtained in four of seven specimens. These results suggest amplification of a novel gene(s). To our knowledge, this is the first formal study of gene amplification in a large consecutively ascertained series of fresh lymphoma biopsies.

Chromosome abnormalities in pancreatic adenocarcinoma

Adenocarcinoma of the pancreas is the fifth most common cause of cancer deaths in the United States, yet few cytogenetic studies of this tumor have been reported. We analyzed 26 primary tumors to identify which chromosome abnormalities occur most frequently in this neoplasm. One carcinoma was well differentiated and mucin producing, 18 were moderately well differentiated, and seven were poorly differentiated. Only normal karyotypes were obtained from nine carcinomas. The remaining 17 carcinomas frequently had normal metaphase cells in addition to simple to highly complex karyotypes. The modal chromosome number in 20 carcinomas was diploid or near-diploid; four carcinomas had both a major near-diploid and near-triploid or near-tetraploid component, and two were near-tetraploid. Numerical abnormalities included loss of whole copies of chromosomes 6, 17, and 18, and gains of chromosome 20. Structural abnormalities were frequent, with 1p, 2p, 3p, 4q, 6q, 7q, 11q, and 17p recurrently involved. Results of this study were combined with karyotypes of 19 other primary adenocarcinomas of the pancreas reported in the literature. The combined data involving 117 breakpoints suggest that careful analysis of chromosome 20, proximal 1q, 6q, proximal 8p, and proximal 17p could be productive in defining genes involved in adenocarcinoma of the pancreas.

Rieger syndrome revisited: experimental approaches using pharmacologic and antisense strategies to abrogate EGF and TGF-alpha functions resulting in dysmorphogenesis during embryonic mouse craniofacial morphogenesis

The major manifestations of Rieger syndrome (RS), an autosomal dominant disorder, include absent maxillary incisor teeth, malformations of the anterior chamber of the eye, and umbilical anomalies [Aarskog et al., 1983: Am J Med Genet 15:29-38; Gorlin et al., 1990: "Syndromes of the Head and Neck" 3rd ed.]. Linkage of RS to human chromosome 4q markers has been identified with tight linkage to epidermal growth factor (EGF) [Murray et al., 1992: Nat Genet 2:46-48]. Mutations associated with genes of the EGF superfamily are implicated in malformations arising from abnormal development of the first branchial arch [Ardinger et al., 1989: Am J Hum Genet 45:348-353; Sassani et al., 1993: Am J Med Genet 45:565-569]. Down-regulation of EGF during early mouse development results in ablation of tooth formation [Kronmiller et al., 1991: Dev Biol 147:485-488]. Since EGF, TGF-alpha, and EGF receptor (EGFr) transcripts are expressed in the mouse first branchial arch and derivatives, experimental strategies were employed to investigate the consequences of down-regulation of EGF translation and inhibition of EGF receptor during embryonic mandibular morphogenesis. Antisense inhibition of EGF expression produces mandibular dysmorphogenesis with decreased tooth bud size; these effects are reversed by the addition of exogenous EGF to the culture medium [Shum et al., 1993: Development 118:903-917]. Tyrphostin RG 50864, which inhibits EGF receptor kinase activity, inhibits EGF or TGF-alpha stimulation of tyrosine phosphorylation in a concentration-dependent manner and severely retards mandibular development [Shum et al., 1993: Development 118:903-917].(ABSTRACT TRUNCATED AT 250 WORDS)

Karyotype and FISH analysis of a newly established cell line derived from a human bladder carcinoma

A new human malignant urologic cell line was established in vitro from a moderately differentiated transitional cell carcinoma of the bladder and cytogenetically characterized. Repeated chromosome analyses of the cell line using conventional RHG and GTG banding and non-radioactive in situ hybridization showed a stable karyotype with a modal number of 48 and chromosomal rearrangements, some of which have not been previously described. Numerical deviation included three trisomies (+7, +8, +9) and one nullisomy (-19, -19). Structural changes involved a balanced translocation (1;5)(q12;q12), an isochromosome 3q, a 14p+, and two markers. Fluorescence in situ hybridization (FISH), using biotin-labeled alpha satellite probes for chromosome 9 or painting for chromosomes 1 and 8, applied to interphase nuclei or metaphases showed similar results to those found by conventional cytogenetic study. This cell line may be an interesting model for fuller characterization by molecular biology studies and for testing anti-cancer drugs in vitro.

Regulation of thyroid hormone receptor beta-2 mRNA levels by retinoic acid

The thyroid hormone receptor, TR beta-2, whose expression is limited to the pituitary and parts of the central nervous system, is strongly negatively regulated at the pre-translational level by thyroid hormone (T3). We have investigated whether retinoic acid (RA), whose receptors (RARs) share a high degree of homology with the thyroid hormone receptors (TRs), can regulate this gene in a manner similar to T3, as has been shown for the growth hormone (GH) gene. GH3 cells were incubated with 10 nM T3, 1 microM RA or both for 48 h and then TR beta-2 mRNA levels determined by RNA blot hybridization analysis. We observed a 73% decrease in TR beta-2 mRNA levels after incubation with T3 and a two-fold increase in TR beta-2 mRNA levels after incubation with RA alone. In the presence of RA, the T3 effect on TR beta-2 mRNA levels was blunted with mRNA levels decreasing by only 20%. We investigated the mechanism by which retinoic acid increases and opposes the effects of T3 on levels of TR beta-2 mRNA. In transient transfection experiments using a reporter plasmid containing the TR beta-2 promoter and in nuclear run on assays, we found no effect of RA on TR beta-2 gene transcription. We then investigated whether the effects of RA were mediated at the post-transcriptional level. Determination of the apparent half-life of TR beta-2 mRNA using the transcriptional inhibitor, actinomycin D, showed that RA had no effect on TR beta-2 mRNA stability.(ABSTRACT TRUNCATED AT 250 WORDS)

Deletion (7)(p11p15) in a patient with Philadelphia-positive chronic myelogenous leukemia

We report a case of chronic myelogenous leukemia (CML) with a Philadelphia (Ph) chromosome. During the transformation phase of the disease, a del(7)(p11p15) and a +Ph were identified as additional chromosomal anomalies. We believe that loss of the segment 7p11-->p15 may play an important role in the progression of the disease.

Oncogenes: cause or consequence in the development of glial tumors

Recent developments in the field of oncogenes and growth stimulatory factors have provided limited but essential models in neuro-oncology. The observation in gliomas of platelet growth factor (PDGF)-like immunoreactivity fits with the autocrine secretion model, rising the possibility for the growth factor independence of the cancer cells. The discovery of the tumor suppressor genes, for which loss of function mutations are oncogenic as in the RB gene of the retinoblastoma and p53 gene, has introduced a new concept of oncogenesis which could be useful even in the cure of the neoplasms. Several oncogenes are amplified and/or expressed in brain tumors, some associated with polymorphism leading to abnormal protein products. Therefore, corresponding functions, such as production of deficient epidermal growth factor receptor (EGFR) encoded by erb-B, are impaired. Abnormal chromosomal patterns have been recognized in brain tumors and found mainly in chromosomes 7 and 22 on which oncogenes erb-B and sis are located, respectively. Location of proto-oncogenes, which are normally expressed in the brain, indicate that they share common distribution patterns mainly involving the cerebellum, hippocampus and olfactory bulbs. These proto-oncogenes may be regulated by physiological and pathological events. The concept of oncogene involvement in brain tumors must be extended to include the other factors such as G-proteins, growth factor receptors, membrane-associated and cytoplasmic protein kinases, which are all responsible for the control of the cell growth and their response to external signals including chemotherapeutic drigs.

1,25-Dihydroxyvitamin D3 increases epidermal growth factor receptor gene expression in BT-20 breast carcinoma cells

In the breast cancer cell line BT-20 which displays a high number of Epidermal Growth Factor Receptors (EGF-R), we have previously observed that 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) at low concentration (0.1 nM) significantly reduces the proliferation rate while it upregulates the EGF binding capacity. The aim of the present investigation was to analyze EGF-R mRNA expression in 1,25-(OH)2D3 treated BT-20 cells. It is found that in cells treated for several days, the EGF-R mRNA levels are increased in relation to the dose from 0.01 to 1 nM. To investigate the time course of the response, cells received the drug only once and were harvested at different times. The data suggest that the stimulation of EGF-R mRNA expression is dose- and time-dependent. Therefore, the increased EGF binding capacity previously demonstrated can be related to the increase of EGF-R transcript levels.

Isolation and characterization of a cDNA encoding a chicken beta thyroid hormone receptor

We have isolated and characterized a cDNA encoding a chicken beta homolog of c-erbA, or thyroid hormone receptor (TR). Chicken liver cDNA libraries were screened with a rat TR beta-1 cDNA probe, and several cDNA inserts were isolated and characterized. The sequence of one cDNA predicts a 369-amino-acid open reading frame (ORF), with a protein sequence that possesses 96% identity with that of rat TR beta-1, but only 88% identity with chicken TR alpha. These data indicate that the cDNA likely encodes a beta form of TR that has the expected putative DNA and T3 binding domains. The chicken TR beta (chTR beta) in vitro translated protein binds T3 with high affinity, and binds both the thyroid hormone response element (TRE) from the rat growth hormone gene and the Xenopus vitellogenin A2 gene estrogen response element (ERE), similarly to that of the rat TR beta-1. Northern blot analysis revealed the expression of a 7.0-kb RNA in several tissues including cerebellum, pituitary, kidney, and liver. This chicken liver TR beta cDNA sequence varies in both the 5' and 3' untranslated regions from the chicken kidney TR beta cDNA sequence recently reported (Forrest et al., 1990). The 5' untranslated cDNA sequence divergence occurs near a potential splice site junction of the human TR beta gene, suggesting that this chicken liver cDNA may represent an alternatively spliced RNA product of the chicken TR beta gene.

Localization of the alpha-like globin gene cluster to region q12 of rabbit chromosome 6 by in situ hybridization

The rabbit (Oryctolagus cuniculus) alpha-like globin gene cluster (HBAC) contains several block duplications of zeta-, alpha and theta-globin genes. Using in situ hybridizations to metaphase chromosome spreads, the gene cluster has been mapped to region q12 of chromosome 6. Given that human HBAC maps to the short arm of chromosome 16, the mapping of rabbit HBAC to 6q12 confirms the assignment of homology between OCU6q and HSA16p based on similarities of chromosomal banding patterns. In both species, HBAC is in a very G + C-rich region within the most distal band of the chromosome.

DNA methylation and oncogene expression in methapyrilene-induced rat liver tumors and in treated hepatocytes in culture

Continued exposure of rats to carcinogenic doses of methapyrilene (MP) leads to elevated levels of 5-methyl-deoxycytidine (5MC) in liver DNA. Since gene expression often correlates with DNA methylation, we investigated these parameters in the MP-induced hepatocellular carcinomas of Fischer 344 rats. DNA was hypermethylated in liver tissue surrounding the tumors relative to liver tissue of untreated controls of the same age, while tumor DNA was not; DNA methylation declined to normal levels when MP treatment ceased. Gene expression analysis showed measurable levels of mRNA for c-Ki-ras, erb-B, erb-B2, hck, src, lyn, vav, trk, raf-1, l-myc, c-jun, c-yes, c-myc, c-abl, and p53. No significant differences in expression for these and other oncogenes were seen between tumors and surrounding livers, although erb-B2 and vav showed visible decreases compared with normal liver. Hypermethylation of DNA and expression of these oncogenes in MP-treated tissues were not correlated. Levels of mRNA for the same genes in MP-treated hepatocytes in culture were similar to in vivo levels; analysis of DNA synthesis levels showed that this gene expression pattern occurred in the absence of proliferation bursts or toxicity in these cells, thus suggesting that treatment in vivo may produce the same results.

Chromosome alterations in 21 non-small cell lung carcinomas

Cytogenetic analysis was performed on 16 primary tumors, 2 effusions, and 3 cell lines from 21 patients with non-small cell lung cancer (NSCLC). In 20 patients specimens were obtained prior to initiating cytotoxic therapy. Extensive clonal chromosome alterations were found in all cases. The most frequent numerical changes were polysomy 7 and polysomy 20 (each seen in 12 specimens). In addition, tumor cells from another six cases exhibited partial trisomy 7, with the shortest region of overlap (SRO) at 7p11-p13. Rearrangements of chromosomes 1, 3, 6, 8, 11, 15, 17, and 19 were each observed in nine or more tumors. Breakpoints were clustered at several chromosomal sites, including 1p13, 3p13, 15p11-q11, 17p11, and 19q13. Recurrent loss involving 1p, 3p, 6q, 11p, 15p, 17p, and 19q were each seen in at least eight cases. The SRO of 3p losses was at band 3p21. Double minute chromosomes were found in three tumors. Overall, our findings indicate that even though karyotypes in newly diagnosed NSCLC are very complex, recurrent cytogenetic changes can be identified. The high incidence of loss of 17p (14 of 21 specimens) appears to be compatible with reports implicating the TP53 gene (at band 17p13) as a frequent site for genetic alteration in lung cancer. Moreover, the recurrence of loss of 3p (12 cases) and 11p (10 cases) is also consistent with recent molecular evidence. The existence of other "hot spots" for cytogenetic change, particularly those involving specific regions on chromosomes 7, 15, and 19, warrants further molecular investigation of these sites in NSCLC.

Polysomy of chromosome 7 is associated with amplification and overexpression of the EGF-receptor gene in a human carcinoma cell line derived from a brain metastasis

Overexpression of the EGF-receptor gene is associated with the malignant nature of some tumors. We have recently reported the establishment of a human carcinoma cell line (T-CAR1), derived from a brain metastasis, that had 7 million EGF receptors per cell and was growth inhibited by EGF. The present study was carried out in order to further characterize the EGF-receptor protein in T-CAR1 cells, and to see if the overexpression of the EGF-receptor gene in these cells was associated with abnormalities at the genomic level. We have compared the T-CAR1 cells with the human glioblastoma cell line T-MG1, which has 135,000 EGF-receptors and is growth stimulated by EGF. The MW of the EGF receptors in T-CAR1 cells and T-MG1 cells was estimated to be 170 kDa, equal to the normal EGF-receptor. However, in T-CAR1 cells an additional protein reacted with the monoclonal antibody directed against the internal domain of the EGF receptor. The levels of EGF receptor-related RNAs in T-CAR1 cells and T-MG1 cells reflected the number of EGF receptors in these cell lines. The EGF-receptor gene was amplified ten-fold in T-CAR1 cells, while it was not amplified in T-MG1 cells. No restriction fragment length polymorphism of DNA digested with various restriction enzymes was seen in either of the cell lines. Chromosomal analysis of T-CAR1 cells showed polysomy of chromosome 7 and marker chromosomes derived partly from chromosome 7. Thus, in the T-CAR1 cell line it was an association between polysomy of chromosome 7 and EGF-receptor gene amplification.

The gene for 17 beta-hydroxysteroid dehydrogenase maps to human chromosome 17, bands q12-q21, and shows an RFLP with ScaI

The gene encoding human 17 beta-hydroxysteroid dehydrogenase (17-HSD; EC 1.1.1.62) is assigned to chromosome 17 by Southern blotting analyses of panels of human x rodent somatic cell hybrids and independently to 17q12-q21 using chromosomal in situ hybridization. A search for physical linkage between 17-HSD and the proto-oncogenes. THRA1 and ERBB2 (both reported to be located in this region of chromosome 17) was performed by pulsed-field gel electrophoresis (PFGE) using several rare-cutting restriction endonucleases. Because all three genes hybridized to DNA fragments of different lengths it seems unlikely that the gene for 17-HSD is located very close to THRA1 and ERBB2. Further evidence for this assumption was obtained from the absence of any coamplification of the 17-HSD gene in 9 breast tumors with amplification of the ERBB2 gene. Analyses of Southern blots of ScaI-digested DNAs from unrelated individuals from Northern Finland revealed a relatively infrequent diallelic restriction fragment length polymorphism, the allele frequencies of which were 0.04 (A1) and 0.96 (A2).

Epidermal growth factor receptor overexpression and trisomy 7 in a case of Barrett's esophagus

Increased expression of epidermal growth factor receptor linked with abnormalities of chromosome 7 has been described in a number of malignancies, but not in premalignant lesions. We report on one patient of nine studied with Barrett's esophagus who had trisomy 7 and showed increased expression of epidermal growth factor receptor. Southern blot analysis demonstrated that the protooncogene c-erb-B, which encodes the epidermal growth factor receptor, was not amplified. However, increased expression of the corresponding mRNA was evident on dot blot analysis. Epidermal growth factor (EGF) binding studies were consistent with increased expression of the receptor with approximately 2.3 x 10(5) molecules of EGF bound per cell. These data suggest that chromosome 7 abnormalities can occur in Barrett's esophagus.

Cytogenetic study of four cancers of the prostate

We cytogenetically studied four cases of adenocarcinoma of the prostate. All tumors were moderately differentiated or well-differentiated, with different degrees of invasion. One tumor with microscopic seminal vesicle invasion and lymph node metastasis (tumor 4) had trisomy 7 as a sole clonal abnormality, suggesting that this is a primary change in some prostatic tumors. Although only normal karyotypes were observed in the other three tumors, several nonclonal changes were evident. Monosomy 9 or deletion of the long arm of 9 was observed in at least one cell in the three tumors without trisomy 7. Furthermore, in one of these tumors (tumor 3, moderately differentiated), several rearrangements (five of 26 cells) were observed, two of which had a common breakpoint at 15q11. Although complex chromosome changes including del(10q) and del(7q) have been described in prostatic tumors, they were not observed in the four tumors studied. This is the first report of a prostate tumor with trisomy 7 as a single clonal chromosome abnormality.

Cloning and characterization of the t(15;17) translocation breakpoint region in acute promyelocytic leukemia

A reciprocal chromosomal translocation, t(15;17)(q22;q11.2-12), is characteristic of acute promyelocytic leukemia (APL) of French-American-British (FAB) subtype M3, and is not associated with any other human malignancy. The non-random pattern of the APL translocations suggests that specific genes on chromosomes 15 and 17 are somehow altered or deregulated as a consequence of the rearrangement. Translocation breakpoints in APL patients provide physical landmarks that suggest an approach to isolating the APL gene(s). Genetic and physical maps constructed for the APL breakpoint region on chromosome 17 have indicated that two fully-linked DNA markers, defining loci for THRA1 and D17S80, map to opposite sides of an APL breakpoint yet reside on a common 350-kb Clal fragment. Cosmid-walking experiments to clone this APL breakpoint have revealed a 38-kilobase deletion on chromosome 17. Studies in additional APL patients have shown that the breakpoint region on chromosome 17 spans at least 80 kilobases.

Activation of cancer cell proteases and cytotoxicity by EGF and PDGF growth factors

The biological effects of EGF and PDGF growth factors on A172 and hEGFr-3T3 cell lines were studied using RBC induced cytolysis and polyacrylamide-gelatin gel electrophoresis assays. The authors report that growth factor-induced cytotoxicity in these cells is mediated by proteolytic enzymes. Treatment of A172 cells with either EGF or PDGF resulted in marked increase of their cytotoxicity (Release Index = 150%). Similarly, RBC induced release index by hEGFr-3T3 cells was elevated to 420% in the presence of 3.4 pM of EGF. However, in A172 cells, PDGF did not have a significant effect on DNA and protein synthesis indicating that stimulation of proteolytic activity is independent of the growth factor signaling pathway. Growth factor induced cytotoxicity was significantly reduced by protease inhibitors in both cell lines. Using EDTA and leupeptin several proteolytic species were identified and localized to cellular membranes as evidenced by polyacrylamide-gelatin electrophoresis assay. These data suggest that growth factors regulate the activation or secretion of proteolytic enzymes in cancer cells and may mediate the invasive and metastatic behavior of these cells.

Epidermal growth factor receptor expression in a retinoic acid-treated human melanoma cell line

Treatment of a human cell line (HXG-2), established from a metastatic melanoma, with retinoic acid (RA) induced morphologic differentiation and eliminated its cloning capacity in soft agar. With the v-erb B oncogene as a probe, slot blot hybridization of genomic DNA from parental HXG-2 cells did not show epidermal growth factor (EGF) receptor gene amplification as compared with normal diploid fibroblasts. Analysis of RNA as well as EGF receptor determinations from HXG-2 and RA-treated HXG-2 cells showed essentially no differences, indicating that RA treatment does not modulate EGF receptor gene expression. Although enhanced EGF receptor expression is found in some advanced-stage melanomas, RA-induced changes in the transformation phenotype of cell line HXG-2 probably do not result from modulation of the EGF-mediated pathway.

Localization of a human T-cell-specific gene, RANTES (D17S136E), to chromosome 17q11.2-q12

We report here the localization of the gene for a human T-cell-specific molecule, designated RANTES, to human chromosome region 17q11.2-q12 by in situ hybridization and analysis of somatic cell hybrids using a cDNA probe to the gene. We have recently shown that this gene, which encodes a small, secreted, putative lymphokine, is a member of a larger gene family some of whose members reside on chromosome 4 but most of whose members have not to date been mapped. A secondary hybridization peak was noted on the region of human chromosome 5q31-q34, which may represent the location of other members of the gene family. Interestingly, this latter region overlaps with the location of an extended linked cluster of growth factor and receptor genes, some of which may be coregulated with members of the RANTES gene family.

Thyroid hormone action and the erbA oncogene family

In this review, we discuss the biological action and biochemical function of the v-erbA oncogene product, and the role of c-erbA proto-oncogene products as thyroid hormone receptors, as related to the molecular structure and function of the nuclear hormone receptors at large.

Chromosome 17p loss in carcinoma of the cervix uteri

Markers derived from chromosome 17 were present in 13 (42%) of 31 carcinomas of the cervix uteri. Altogether, 14 such markers were present, ten of which were 17p+ chromosomes with a small amount of additional material, probably of variable origin, while three were i(17q)s. The significance of the chromosome 17 aberrations in cervical carcinoma may lie in the loss of recessive genes on 17p.

Multiple tandem 18-kb sequences clustered in the region of the acute promyelocytic leukemia breakpoint on chromosome 17

This paper describes the cloning of an 18-kb sequence present in approximately 30 copies on chromosome 17. Most of these are clustered in the region of the breakpoint associated with acute promyelocytic leukemia (APL). These copies map both above and below the breakpoint, and pulsed field gel analysis indicates that the majority of these sequences lie within a region of approximately 2 megabases. The organization of these sequences appears to be that of large imperfect palindromes.

Chromosomal mapping of human keratin genes: evidence of non-linkage

We have determined the chromosomal location of the genes for the human keratin intermediate filament proteins K1 (type II; 67 kDa) and K10 (type I; 57 kDa) by the use of specific cDNA clones in conjunction with somatic cell hybrid analysis and in situ hybridization. The K1 keratin gene maps to chromosome region 12q11----q13; the K10 keratin gene maps to chromosome region 17q12----q21. Each gene has been mapped relative to other genes known to be localized on chromosomes 12 and 17, respectively. In somatic cell hybrid analysis, the K1 gene segregates concordantly with the Hox-3 homeo box gene cluster at chromosome region 12p12----q13. The K10 gene localizes to a region proximal to a breakpoint at 17q21 which is involved in a t(17;21)(q21;q22) translocation associated with an acute leukemia. K10 appears to be distal (telomeric) to the gene loci for G-CSF, erb-A, and Her-2, which map to chromosome region 17q12----q21. The NGFR gene and Hox-2 homeo box locus are localized distal to the 17q21 break point and thus distal to the K10 gene. These data demonstrate that keratin genes K1 and K10, which are coexpressed in terminally differentiated epidermis, are not linked in the human genome, implying the existence of trans-acting factors involved in the regulation of expression of these genes.

Mega base map of the epidermal growth factor (EGF) receptor gene flanking regions and structure of the amplification units in EGF receptor-hyperproducing squamous carcinoma cells

We have established a mega base scale physical map of the 5'- and 3'-flanking regions of the epidermal growth factor (EGF) receptor gene using CpG-recognition rare-cutting restriction enzymes and pulsed-field gel electrophoresis. In this map, a methylation-free CpG island (HTF island) is located within an 8-kilobase pair (kb) EcoRI fragment which includes exon 1 of the EGF receptor gene. From this HTF island, a 390-kb NotI fragment was identified as the longest 5'-flanking region and a 540-kb MluI fragment as the longest 3'-flanking region. Utilizing this map information, we have analyzed the structure of the flanking regions of amplified EGF receptor genes which are found in various squamous carcinoma cells. Among seven cell lines tested, four cell lines carrying EGF receptor genes in amounts more than 20 times that of normal cells showed amplification together with large 5'- and 3'-flanking regions. The amplified 5'-flanking regions were rearranged in different forms but were distinct in each cell line. The amplified 3'-flanking regions were at least 540 kb in size and common to all the cell lines, except that A431 had rearrangement points within 540 kb downstream of the HTF island. Thus, the size of amplification units appears to be large and different in each cell line.

Assignment of estradiol receptor gene to mouse chromosome 10

Differences in restriction fragment lengths were detected with murine estrogen receptor cDNA (clone MOR-100) between Chinese hamster and mouse. These were used to determine the chromosomal location of the estrogen receptor in the mouse by Southern blot analysis of DNAs obtained from a panel of mouse-Chinese hamster somatic cell hybrids. The mouse estrogen receptor gene was localized on mouse chromosome 10.

Mapping of the human retinoic acid receptor to the q21 band of chromosome 17

Recombinant plasmid containing cDNA insert from the human retinoic acid receptor was radiolabeled and hybridized in situ to metaphase chromosome preparations. The results localized the human retinoic acid receptor to the q21 band of chromosome 17.

A hypothesis regarding the development of acute myeloid leukemia from preleukemic disorders. The role of protooncogenes

Acute nonlymphocytic leukemia is often preceded by a preleukemic phase that can be characterized by a reduction in hematopoiesis, by ineffective hematopoiesis, or by a myeloproliferative/myelodysplastic state. The time between onset of the preleukemic state and the appearance of leukemia is quite variable, and at times such evolution does not occur. These clinical observations are compatible with the multistep hypothesis of tumor development. In studies underway in our laboratory, chronic myelogenous leukemia (CML) is being used as a model system to study the steps in and possible mechanisms underlying the development of preleukemia and its evolution to acute leukemia. Chronic myelogenous leukemia is particularly suited for this role because the chronic phase of the disease is an easily identifiable myeloproliferative state that invariably evolves into acute leukemia. In the discussion that follows, this clinical entity is used to develop a general model for the preleukemias and their evolution to acute leukemia.