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Evidence for microsatellite instability in bilateral breast carcinomas.

The molecular pathogenesis of various categories of breast cancer (BC) has been well described, but surprisingly few reports have appeared on analysis of somatic mutations in bilateral BC. We have performed a polymerase chain reaction (PCR)-driven investigation of chromosomal regions showing common loss of heterozygosity (LOH) in 23 cases (46 tumors) from patients diagnosed with bilateral BC. LOH was observed in 15/46 (33%) informative tumors for chromosome 1p, 5/32 (16%) for 5q, 12/44 (27%) for 11q, 15/40 (38%) for 13q and 4/24 (17%) for 17p. These values are within the range of interlaboratory variations reported for unilateral BC. There was no strong evidence for concordance of LOH within the same patient for any of the chromosomal loci tested. Atypical for breast carcinomas, 7/46 (15%) tumors accumulated a high frequency (ranging from 11 to 29%) of shortened dinucleotide CA repeats, implying microsatellite instability (MI). Further analysis with the highly informative BAT-26 marker allowed for the classification of two of these tumors as having a replication error positive (RER(+)/MSI-H) phenotype, whereas the remaining five carcinomas harbored so-called borderline MI. Thus an involvement of both RER(+) and borderline MI appears to be a distinct feature of bilateral breast carcinomas compared to unilateral lesions.

Adult↗

[A study of neuroleptic malignant syndrome in the presenium and senium].

Recently, with the increase in elderly population, we have had more opportunities to administer neuroleptics to elderly patients for hallucinatory delusional state, delirium, psychomotor excitement, wandering etc. However, little is known about the characteristics of the neuroleptic malignant syndrome (NMS) in elderly patients, which is the most serious side effect of neuroleptics. In this paper, we present the clinical course of five NMS patients in the presenium and senium. Case 1 was 72-year-old male who was diagnosed as having dementia of Alzheimer's type (with late onset). He showed nocturnal wandering, insomnia, and irritability. Tiapride 60 mg per day had been administered previously. Just after the addition of oxypertine 10 mg per day, NMS occurred, and he died of pneumonia a week later. Case 2 was 75-year-old male who was diagnosed as having vascular dementia. He showed insomnia, hyperactivity and wandering. He had been given levomepromazine (LPZ) 10 mg per day over a long period of time. At first, he had daily episodic fever, however, serum CPK levels did not increase at that time. A month later, all the symptoms of NMS appeared and then the patient's condition suddenly deteriorated and he died three days later. Case 3 was a 64-year-old male who was diagnosed as having dementia of Alzheimer's type (with early onset). He showed insomnia, irritability and violence. Tiapride 50-125 mg per day was administered along with oxypertine 50-115 mg per day. Almost two months later, NMS occurred. He had daily episodic fever at first, extrapyramidal symptoms and autonomic instabilities gradually increased. Soon after symptoms of NMS were completed. In this case, NMS seemed to be induced by bacterial pneumonia after long term administration of LPZ 5 mg per day. Case 4 was a 75-year-old female who was diagnosed as having dementia of Alzheimer's type (with late onset). She showed hallucinatory delusional state. Although she had autonomic instabilities just after adminstration of haloperidol 1-2 mg per day, NMS itself occurred after discontinuing the neuroleptic. Case 5 was a 61-year-old female who was diagnosed as having schizophrenia at the age of forty. She was given various neuroleptics over a period of time. The neuroimaging in SPECT showed her cerebral cortex was generally hypoactive. She had a tendency to have autonomic instabilities after the administration of relatively high potential neuroleptics. Risperidone 3-6 mg per day was administered, and almost a month later, autonomic instabilities increased and she was diagnosed as having NMS. All the patients would be able to have brain dysfunction, which suggested that such patients may be liable to NMS. In our patients, NMS occurred after the additional administration of oxypertine 10 mg per day or after long time administration of LPZ 5 mg per day. It was suggested that NMS could occur after the administration of low dose and relatively low potential neuroleptics in elderly patients. Our 3 of 5 patients showed the delayed type of NMS, which might be relatively more frequent in senior and presenior patients than in younger patients. In case 3, NMS was induced by the somatic disease (bacterial pneumonia), however in other cases, NMS was not always induced by somatic disease. Our 4 of 5 patients experienced some of the symptoms of NMS--episodic fever, extrapyramidal symptoms and autonomic instabilities--before the onset of NMS. Such symptoms may be "pre-steps" to NMS. Once NMS occurred, the patient's systemic condition tended to deteriorate acutely. Due to the fact that our 2 of 5 patients died, it was suggested that the prognosis of the NMS patients in presenium and senium tends to be much worse. It is important to find the "pre-steps" to NMS and treat them as soon as possible for better prognosis.

Aged↗

Structural instability of a transgene locus in tobacco is associated with aneuploidy.

This paper describes molecular and cytogenetic evidence for the stability of a transgene locus that is present on the triplicated chromosome in an aneuploid tobacco line. This instability was manifested in several ways in trisomics including a major chromosome rearrangement that was detectable cytogenetically, smaller scale DNA rearrangements that occurred both germinally and somatically, and methylation/epigenetic silencing. In a deletion derivative of the locus, DNA breakpoints were found in AT-rich regions. One of these regions binds to nuclear scaffolds in vitro, suggesting a possible role for aberrant topoisomerase II cleavage in destabilization of the locus. The implications of increased chromosome instability in aneuploids for plant karyotype evolution and human carcinogenesis are discussed.

Aneuploidy↗

Granulocyte colony-stimulating factor administration upregulates telomerase activity in CD34+ haematopoietic cells and may prevent telomere attrition after chemotherapy.

Hematopoietic reconstitution could be associated with premature ageing of the transplanted cells and a high frequency of myelodysplastic syndrome and secondary leukaemia. Telomere length decreases with cell divisions and age, and at a crucial length it is associated with chromosomal instability and cell senescence. Telomerase is a reverse transcriptase enzyme that adds nucleotides to chromosomal ends. Most somatic cells lack telomerase activity yet haematopoietic stem cells retain low levels of telomerase. Some studies have found that chemotherapy and stem cell transplantation lead to the accelerated shortening of telomere length. As granulocyte colony-stimulating factor (G-CSF) is routinely used in the mobilization of stem cells for transplantation, we evaluated its effects on telomerase activity and regulation, and on telomere dynamics, in normal donors and selected lymphoma patients. Administration of G-CSF increased telomerase activity in CD34+ haematopoietic cells compared with controls. In marrow-derived CD34+ cells, telomerase activity increased sevenfold, compared with a 14-fold increase in peripheral-blood-mobilized CD34+ cells. A parallel increase in the expression of human telomerase enzyme reverse transcriptase RNA and protein kinase C alpha occurred. In addition, G-CSF administration to five lymphoma patients after consecutive courses of CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) chemotherapy, resulted in telomere length preservation or elongation, as opposed to marked attrition in patients who did not receive growth factors. We conclude that the in vivo administration of G-CSF prevents or attenuates telomere attrition associated with chemotherapy administration. This attenuation may contribute to the preservation of telomere integrity inG-CSF-primed transplanted stem cells.

Aged↗

Direct single gene mutational events account for radiation-induced intestinal adenoma yields in Apc(Min/+) mice.

Data on the induction of small intestinal tumors, predominantly adenomas, by X radiation in Apc(Min/+) mice are reported. Comparison of these incidences with estimates of radiation-induced direct single gene mutation frequencies taken from the literature support the hypothesis that direct mutational loss of Apc+ is the sole requirement for initiation of adenoma. Furthermore, estimates of radiation-induced initiation of adenoma per target stem cell in this animal model are similar to or less than radiation-induced direct somatic gene mutation frequencies. Therefore, while the data reported here do not preclude a role for genomic instability in tumor progression, it is not necessary in this model to postulate the involvement of radiation-induced transmissible genomic instability in initiation of intestinal adenoma.

Adenoma↗

Increased cancer risk as a genetic effect of ionizing radiation.

The well known genetic effects of ionizing radiation include severe developmental disorders in the progeny of irradiated parents resulting in embryonic death, stillbirth and early postnatal mortality, congenital abnormalities, malformations and fertility disturbances in live-born organisms. These effects are considered to be due to gross mutations (genomic, chromosomal and those of essential genes). Physiological inferiority and an increased cancer risk in phenotypically normal offspring of irradiated parents appear to be two further types of genetic effect of radiation. The genetic background of these effects is suggested to be induced recessive polygene mutations and regulatory DNA alterations, which may lead to instability of the hereditary apparatus of cells, activation of protooncogenes and other inducible processes. A comparison of somatic and genetic effects of radiation shows certain similarities, not only in phenomenology, but probably also in pathogenetic mechanisms.

Animals↗

[Psychosomatic medicine and psychoanalytic observation: considerations on the mechanism of symptom formation].

The clinical symptom, perceived at body level, such as pain, dyskinesia, circulatory changes (tachycardia, blushing, pallor) is intrinsic and simultaneous with parallel changes at the mind level, such as anxiety, sorrow, instability, joy, depression and shame. Therefore, it has to be distinguished within the symptom, the overt component - somatic alterations - and the latent component - changes in mental processes. Hence, the global psychosomatic nature is intrinsic to the clinical symptoms.

Anxiety↗

Suicidal thoughts among adolescents: an intercultural approach.

Two epidemiological surveys of suicidal ideation were conducted among adolescents, aged 15-18, in France and the Canadian province of Quebec. The results suggest that, in both countries, suicidal ideation was linked to drug use (especially tobacco, illicit drugs, and psychotropic medicine), nonspecific somatic complaints (especially tiredness, sleep difficulties, depression, and feeling tense), a lack of self-esteem (pessimism, instability, boredom), and dissatisfaction with family relationships. There was no relationship between suicidal ideation and sports activities in either country. The implications for prevention are discussed.

Adolescent↗

Lack of association between microsatellite instability and benign adrenal tumors.

BACKGROUND: The adrenal gland may give rise to pheochromocytomas, which are catecholamine-producing tumors originating from the adrenal medulla, or to adrenocortical tumors, which derive from the adrenocortical cortex and may be secreting or not. The genetic mechanisms underlying the formation of these tumors include somatic mutations in susceptibility genes, especially in the familial forms, and allelic loss, especially in chromosome 1. AIM: The aim of this study was to investigate a third genetic mechanism by evaluating microsatellite instability using the reference markers (Bat25, Bat26, D2S123, D5S346, D17S250) validated by the National Cancer Institute. Microsatellite loci were analyzed in 32 benign tumors, including 11 pheochromocytomas and 21 adrenocortical tumors, in patients with and without familial syndrome. RESULTS: The different alleles of microsatellite loci were reliably detected by DNA fragments analysis, whereas data obtained after melting-point analysis on the Lightcycler were inconsistent. No microsatellite instability was detected in any tumor. One patient with a unilateral pheochromocytoma showed a loss of heterozygosity for D17S250. A second patient with a MEN-2A syndrome and a two-sided pheochromocytoma exhibited a loss of heterozygosity for D2S123 in the right tumor only and a retention of heterozygosity for all markers in the left tumor. CONCLUSIONS: These results suggest that microsatellite instability, evaluated by the five reference markers of the National Cancer Institute, is not a feature of benign adrenal tumors.

Adrenal Gland Neoplasms↗

Evidence for BRAF mutation and variable levels of microsatellite instability in a syndrome of familial colorectal cancer.

BACKGROUND AND AIMS: Recently, an alternative pathway of tumorigenesis has been identified in the colorectum associated with serrated precursor lesions, variable levels of microsatellite instability (MSI-V), and driven in part by activating mutations in the BRAF proto-oncogene (V599E). Somatic BRAF mutations in hereditary nonpolyposis colon cancer (HNPCC) are rarely observed. Here, we discuss their role in the development of other familial colorectal cancers (CRC). We studied non-FAP, non-HNPCC CRC families characterized by tumors that varied in their level of MSI between individual members. METHODS: A subset of tumors from a total of 55 collected (25 polyps and 30 cancers) from 43 individuals across 11 families underwent pathology review, examination for V599E using allele-specific polymerase chain reaction, and for methylation of the MINT31 CpG island. RESULTS: All MSI-V families met the current revised Bethesda Guidelines and 6 of 11 (55%) met the Amsterdam I criteria. V599E was observed in 12 of 19 (63%) polyps and 14 of 20 (70%) cancers (4 of 4 high MSI, 2 of 4 low MSI, and 8 of 12 stable MSI), a significant increase over HNPCC (0 of 15 or 0%), and unselected CRC (30 of 197 or 15.2%) ( P < .05). Eight of the 10 (80%) cancers that underwent analysis showed hypermethylation of MINT31. CRCs showed early age at onset and were more likely to show a serrated architecture than unselected CRCs ( P < .05). CONCLUSION: These data provide evidence that the families described here represent a syndrome of familial CRC that is distinct from HNPCC. High levels of BRAF mutation and MINT31 hypermethylation suggest an origin in the serrated pathway of CRC development.

Colorectal Neoplasms↗

Differences of clinical features, prognosis and genetic mutations in Chinese patients with malignant melanoma and additional primary tumours.

BACKGROUND: The differences in the clinical features, prognosis and genetic mutations in Chinese patients with malignant melanoma (MM) and additional primary tumours remain unclear. METHODS: A retrospective analysis was conducted on patients with malignancies in Fujian Cancer Hospital from January 2007 to September 2022, end follow-up in September 2023. Clinical data were gathered, survival analysis was performed, and genetic mutations were detected. RESULTS: There were 58 of 1223 melanoma patients with melanoma and additional primary tumours, an incidence of 4.74%. Acral MM was the most common subtype (26/58), 23 (39.66%) patients had concomitant digestive tumours. Patients who had MM as their first primary tumour (MMFP) had shorter tumour occurrence intervals (9.93 vs. 57.78&#xa0;months, p&#xa0;=&#xa0;.008) but longer melanoma survival (MM-OS) than the non-MMFP group (100.43 vs. 18.93&#xa0;months, p&#xa0;=&#xa0;.015). Patients with cancer family histories were more likely to have pathogenic and likely pathogenic (P/LP) mutations (2/5 vs. 4/25). The somatic BRAF gene mutation was frequently observed in MM tissue (8/19, 42.11%). Three patients had whole-genome doubling and microsatellite instability-high (MSI-H). The COSMIC2 signature 3 was significantly higher in the P/LP group. CONCLUSIONS: The frequency of MM and additional primary tumours is about 5% in Chinese populations. Patients with melanoma diagnosed first have longer melanoma survival. Digestive system tumours were the most concomitant; a digestive examination is advisable, especially for those with an expected overall survival (OS) greater than 10&#xa0;months. Meanwhile, patient's family cancer history should be followed up in detail, along with completion of germline P/LP mutation and somatic mutation testing, all of which may provide valuable support for further treatment.

Adult↗

Multiple chromosomal associations and paracentromeric region instability in a case of acute leukemia.

A case of acute myelomonocytic leukema is described, which was characterized cytogenetically by the presence of centromeric elongations, somatic crossovers, selective endoreduplication figures, and multiple chromosomal clusters. The demonstration of these phenomena by selective staining techniques for the chromosome bands (Q, C, G and S) and the nucleolar areas (acridine-orange, amido black B 10) raises some biological aspects involved in the proliferation of leukemic cells, such as nucleolar persistance during the metaphase and the non-separation of chromatids in the clusters during the anaphase. These structural abnormalities may represent the background for the explanation of the appearance of subclones in neoplastic disorders.

Adult↗

Somatic frameshift mutations in the BAX gene in colon cancers of the microsatellite mutator phenotype.

Cancers of the microsatellite mutator phenotype (MMP) show exaggerated genomic instability at simple repeat sequences. More than 50 percent (21 out of 41) of human MMP+ colon adenocarcinomas examined were found to have frameshift mutations in a tract of eight deoxyguanosines [(G)8] within BAX, a gene that promotes apoptosis. These mutations were absent in MMP- tumors and were significantly less frequent in (G)8 repeats from other genes. Frameshift mutations were present in both BAX alleles in some MMP+ colon tumor cell lines and in primary tumors. These results suggest that inactivating BAX mutations are selected for during the progression of colorectal MMP+ tumors and that the wild-type BAX gene plays a suppressor role in a p53-independent pathway for colorectal carcinogenesis.

Adenocarcinoma↗

Somatic cell fusion as a source of genetic rearrangement leading to metastatic variants.

Tumor cell populations displaying metastatic properties often have higher gene dosage than their less malignant progenitor tumors, as shown by increased ploidy levels, chromosome duplication and gene amplification. The acquisition by tumor cells of high chromosome numbers may be due to endoreduplication or somatic hybridization either between tumor cells or between tumor and host cells. All such mechanisms increase genetic variability and instability in tumor cells since they trigger a polyploidization-segregation cycle. Among the wide variety of segregants which may emerge from high-ploidy cells, variants with increased malignancy can be positively selected in vivo. Evidence for in vivo fusion of tumor and normal host cells has been reported in different tumor systems. However the attainment by tumor-host hybrids of a higher degree of malignancy has only been observed following substantial chromosome segregation. The involvement of a cell of bone marrow origin as preferential host partner in the fusion process has been proved both by studies on tumor-host hybrids in bone marrow radiation chimeras and in vitro hybridization experiments between non-metastatic tumors and normal lymphoreticular cells which have led to the establishment of metastatic variants. Several different segregational mechanisms may bring about homozygosity or hemizygosity of recessive alleles in tumor-host hybrids, leading to their expression. The marked chromosome dynamics of tumor-host hybrids are also responsible for extensive chromosome rearrangements. At the molecular level these may represent mechanisms causing altered oncogene activity. The activation of new oncogenes by transposition or amplification as well as the amplification of previously activated oncogenes are the mechanisms most likely to be responsible for transition from low to high malignancy, occurring through ploidy changes, such as those produced by somatic mating.

Animals↗

Deregulated expression of c-mos in non-small cell lung carcinomas: relationship with p53 status, genomic instability, and tumor kinetics.

Little is known about the status of the mitogen-activating protein kinase pathways in lung cancer. One of the key molecules taking part in these pathways is the product of the c-mos proto-oncogene, which plays an important role in oocyte maturation. In vitro investigations in somatic cells have shown that c-mos expression has opposing effects on the cell cycle, which suggests that this proto-oncogene may represent an important determinant of aberrant cell function (genomic instability and altered kinetics). A recent study suggests that these effects may be p53 dependent. In view of the apparent link between c-mos and p53, we investigated in a series of 56 non-small cell lung carcinomas: a) the status of c-mos; b) its relationship to genomic instability (aneuploidy) and two kinetic parameters of the tumors, proliferation and apoptotic indexes (AI); and c) its association with p53 alterations and their concomitant relationship with the above parameters. We found c-mos overexpression in 27% of the tumors. Expression was higher in stages II/III (34%) than in stage I (17%; P = 0.018). Complete concordance was observed between c-mos overexpression and elevated c-mos mRNA levels. Because c-mos gene amplification was not detected, its deregulated expression may be attributable to increased transcription. Of the c-mos positive [c-mos(P)] cases, 77% were associated with aneuploidy. Sequencing showed two silent mutations and one missense (R-->L) at codon 22, located in a region critical for c-mos stability. In contrast to the findings of some in vitro studies, c-mos(P) tumors had a lower mean AI score than the c-mos negative [c-mos(N)] tumors had, implying that induction of apoptosis may have been defective. Indeed, 86% of the tumors overexpressing c-mos showed p53 alterations. The carcinomas with concomitant alterations of c-mos and p53 [c-mos(P)/p53 positive] had significantly lower AI values (P < 0.001) and were more frequently associated with aneuploidy (P = 0.015) than the c-mos(N)/p53 negative tumors but not the c-mos(N)/p53 positive tumors, which suggests that p53 status is the main determinant of ploidy status and apoptosis in our series. This finding also strengthens the concept that wild-type p53 plays a "safeguard" role in preventing oncogene-mediated activation.

Aged↗

Extremely complex repeat shuffling during germline mutation at human minisatellite B6.7.

Human minisatellite B6.7 is a highly variable locus showing extensive heterozygosity with alleles ranging from six to >500 repeat units. Paternal and maternal mutation rates to new length alleles were estimated from pedigrees at 7.0 and 3.9% per gamete, respectively, indicating that B6.7 is one of the most unstable minisatellites isolated to date. Mutation at this locus was also analysed by small pool PCR of sperm and blood DNA. Male germline instability varied from <0.8 to 14% per allele and increased with tandem array size. In contrast, the frequency of mutants in somatic (blood) DNA was far lower (<0.5%), consistent with a meiotic origin of germline mutants. Sperm mutants were further characterized by minisatellite variant repeat mapping using four major polymorphic sites within the B6.7 repeats. This highly informative system revealed a wide variety of changes in allele structure, including simple intra-allelic duplications and deletions and more complicated inter- and intra-allelic transfers of repeat blocks, as seen at other human minisatellites. The main mode of sperm mutation, however, resulted in extremely complex allele reorganization with evidence of inter-allelic transfer plus the generation of novel repeats by rearrangement at the sub-repeat level, suggesting that recombinational instability at B6.7 is a complex multistep process.

Alleles↗

Spontaneous length variation in microsatellite DNA from human T-cell clones.

Recently, much interest has been focused on instability of microsatellite DNA sequences such as di- and tri-nucleotide repeats in human cancers. Certain tumors show an increased frequency of mutation leading to repeat length variation at microsatellite loci, and it is thought that such instability may be a marker for the transformed phenotype. However, the spontaneous frequency by which repetitive DNA such as CA-repeats undergoes size changes in normal human somatic cells is not known. Therefore, it is not possible to decide if there is an increase in the frequency of microsatellite mutation in specific tumors or if the change observed simply reflects the frequency of microsatellite mutation in the cell population from which the tumor originates. To investigate this we have established panels of T-lymphocyte clones from 28 healthy males and determined the spontaneous length variations at three CA-repeat markers that are often used to investigate satellite instability: D2S123, D9S180, and D10S197. We found 3 T-cell clones with altered microsatellite size in a total of 178. This corresponds to a background frequency of 3 somatic microsatellite mutations in 1,028 alleles studied, i.e., 2.9 x 10(-3). This frequency is comparable to that found in many tumors of the breast, brain, ovary, and skin but is considerably lower than the frequency of microsatellite mutation in tumors related to hereditary non-polyposis colorectal cancer.

Cell Transformation, Neoplastic↗

Error propagation in viable cells.

Error propagation is the process, predicted by theoretical models, whereby errors in translating the genetic code will beget fresh errors in successive generations. It has been postulated that error propagation may underly the mortality of cells which display clonal senescence. We have demonstrated the occurrence of error propagation in viable cells of E. coli during growth in a low concentration of streptomycin, a drug which promotes ribosomal ambiguity. We monitored error propagation by measuring mistranslation of a specific UAA codon, and measured viability by direct enumeration of both live and dead cells through a sensitive microscopic technique. We find that the error frequency may be artificially increased by at least an order of magnitude without generating any detectable increase in the proportion of dead cells or of cells whose descendents are doomed to clonal senescence. The error frequency increases gradually over the course of a few generations, in qualitative agreement with the notion of error propagation, and eventually stabilizes at a constant value much higher than normal. The kinetics of this increase agree quantitatively with the Hoffman-Kirkwood and Holliday formulation of error propagation, for parameter values which dictate convergence to a stable error frequency. This convergent behaviour, under conditions of enhanced mistranslation, demonstrates that the normal parameters are well removed from the region of instability in error propagation; even an order of magnitude increase in mistranslation does not tip the translation system into the unstable mode which has been postulated to underly cell senescence. Thus, the error catastrophe theory of cell senescence cannot apply to the translation system of bacteria. We have reviewed experimental data on the fidelity of translation in somatic cells of higher organisms which militate against the notion that the translation system in these cell types could be much closer to the region of instability than in bacteria. These considerations controvert the error catastrophe theory of cell senescence.

Alkaline Phosphatase↗