Tissue-specific expression and dietary regulation of chimeric mitochondrial 3-hydroxy-3-methylglutaryl coenzyme A synthase/human growth hormone gene in transgenic mice

We have studied the role of the mitochondrial 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) synthase gene in regulating ketogenesis. The gene exhibits expression in various tissues and it is regulated in a tissue-specific manner. To investigate the underlying mechanisms of this expression, we linked a 1148-base-pair portion of the mitochondrial HMG-CoA synthase promoter to the human growth hormone (hGH) gene and analyzed the expression of the hGH reporter gene in transgenic mice. mRNA levels of hGH were observed in liver, testis, ovary, stomach, colon, cecum, brown adipose tissue, spleen, adrenal glands, and mammary glands from adult mice, and also in liver and stomach, duodenum, jejunum, brown adipose tissue, and heart of suckling mice. There was no expression either in kidney or in any other nonketogenic tissue. The comparison between these data and those of the endogenous mitochondrial HMG-CoA synthase gene suggests that the 1148 base pairs of the promoter contain the elements necessary for expression in liver and testis, but an enhancer is necessary for full expression in intestine of suckling animals and that a silencer prevents expression in stomach, brown adipose tissue, spleen, adrenal glands, and mammary glands in wild type adult mice. In starvation, transgenic mice showed higher expression in liver than did wild type. Both refeeding and insulin injection reduced the expression. Fat diets, composed in each case of different fatty acids, produced similar expression levels, respectively, to those found in wild type animals, suggesting that long-, medium-, and short-chain fatty acids may exert a positive influence on the transcription rate in this 1148-base-pair portion of the promoter. The ketogenic capacity of liver and the blood ketone body levels were equal in transgenic mice and in nontransgenic mice.

Prevention of diabetic alterations in transgenic mice overexpressing Myc in the liver

Recent studies have demonstrated that the overexpression of the c-myc gene in the liver of transgenic mice leads to an increase in both utilization and accumulation of glucose in the liver, suggesting that c-Myc transcription factor is involved in the control of liver carbohydrate metabolism in vivo. To determine whether the increase in c-Myc might control glucose homeostasis, an intraperitoneal glucose tolerance test was performed. Transgenic mice showed lower levels of blood glucose than control animals, indicating that the overexpression of c-Myc led to an increase of blood glucose disposal by the liver. Thus, the increase in c-Myc might counteract diabetic hyperglycemia. In contrast to control mice, transgenic mice treated with streptozotocin showed normalization of concentrations of blood glucose, ketone bodies, triacylglycerols and free fatty acids in the absence of insulin. These findings resulted from the normalization of liver metabolism in these animals. While low glucokinase activity was detected in the liver of diabetic control mice, high levels of both glucokinase mRNA and enzyme activity were noted in the liver of streptozotocin-treated transgenic mice, which led to an increase in intracellular levels of glucose 6-phosphate and glycogen. The liver of these mice also showed an increase in pyruvate kinase activity and lactate production. Furthermore, normalization of both the expression of genes involved in the control of gluconeogenesis and ketogenesis and the production of glucose and ketone bodies was observed in streptozotocin-treated transgenic mice. Thus, these results suggested that c-Myc counteracted diabetic alterations through its ability to induce hepatic glucose uptake and utilization and to block the activation of gluconeogenesis and ketogenesis.

[Alpha interferon treatment in idiopathic hypereosinophilic syndrome resistant to conventional therapy]

The idiopathic hypereosinophilic syndrome (HES) is an infrequent entity defined by an eosinophil count > 1.5 x 10(9)/l and the specific infiltration of different organs not attributable to another disease. Its prognosis is marked by the complications derived from visceral, particularly cardiac, infiltration determining a median survival of less than one year if treatment is not administered. Although a notable prolongation in survival may be achieved in these patients with the administration of glucocorticoids and cytolytic drugs, mainly hydroxiurea, there remains a group of patients who do not respond to these therapeutic measures, thus leading to alpha interferon trials with promising results. A favourable experience with the use of alpha interferon in two patients with IHS resistant to conventional treatment is reported. The first patient presented a picture characterized by diarrhoea, palpitations and effort dyspnea demonstrating heart involvement suggestive of eosinophilic infiltration on echocardiographic study. The second patient presented dyspneic night cough and generalized pruritus in addition to anemia and thrombocytopenia. The administration of alpha interferon (3 x 10(6) U/3 days a week and 3 x 10(6) U/day, respectively) was followed in both cases by the rapid disappearance of the symptomatology, normalization of the hematologic parameters and a reduction of the eosinophilia to values of less than 1 x 10(9)/l. This response has maintained over the two years of control in which the patients have received alpha interferon as a maintenance treatment.

CNS involvement in mantle-cell lymphoma

PURPOSE

In non-Hodgkin's lymphomas, CNS involvement is highly dependent on the histology of the lymphoma. Mantle-cell lymphoma (MCL) is a lymphoma type with distinctive histologic, biologic, and clinical features in which CNS involvement has only been rarely described. The purpose of this report is to describe the incidence, clinical characteristics, and outcome of CNS infiltration in patients with MCL seen at a single institution.

PATIENTS AND METHODS

Twenty-two patients with MCL, who account for 6% of all patients with nodal lymphomas diagnosed and monitored at a university hospital from 1987 to 1994, were studied. Analysis of the incidence of CNS involvement by the disease was performed.

RESULTS

Five of 22 patients (22%; exact 95% confidence interval [CI], 7.8% to 45.4%) with MCL developed CNS involvement at a median of 18 months (range, 6 to 59) from diagnosis. All of these patients presented with poor MCL histologic subtypes and advanced disease. When the CNS infiltration became apparent, all of the patients displayed neurologic signs and had lymphoid cells consistent with the diagnosis of MCL in the CSF. In most of the cases, CNS infiltration was part of resistant disease or generalized relapse and had an ominous significance.

CONCLUSION

The incidence of CNS involvement in MCL might be higher than previously recognized. The frequency of CNS infiltration in MCL deserves to be investigated in other series and, if a high incidence is confirmed, the risk factors, mechanisms, and clinical implications of such a complication should be further studied.

Increased expression of the PRAD-1/CCND1 gene in hairy cell leukaemia

The PRAD-1/CCND1 gene encodes Cyclin D1, a cyclin involved in cell cycle regulation at the G1-S transition. Over-expression of this gene is a highly specific molecular marker of mantle cell lymphomas (MCLs), but it may also be up-regulated in some chronic lymphoproliferative disorders, mainly chronic lymphocytic leukaemia. We have examined PRAD-1/CCND1 gene expression by Northern blot and Western blot analysis in a series of 18 hairy cell leukaemias (HCLs), nine other splenic malignant lymphoproliferative disorders, and three normal/reactive spleens. Over-expression of the mRNA PRAD-1/CCND1 gene was observed in 16/18 HCLs, including one case of hairy cell leukaemia variant, whereas this molecular alteration was not found in other cases examined. mRNA levels varied from case to case, but they were lower than those observed in MCLs. At the protein level, Western blotting analysis showed Cyclin D1 protein expression in the 11 HCLs analysed. No bcl-1 rearrangements were seen with the MTC, p94PS and PRAD-1 (lambda-P1-4) probes used, and no PRAD-1/CCND1 gene amplification was detected in any case. These findings indicate that PRAD-1/CCND1 is over-expressed at mRNA and protein levels in a high number of HCLs. However, the levels of expression are much lower than in MCLs, and this expression is not associated with bcl-1 rearrangements or PRAD-1/CCND1 gene amplification.

Presenting features, natural history, and prognostic factors in localized non-Hodgkin's lymphomas: analysis of 117 cases from a single institution

Clinical features and prognostic factors were analyzed in a series of 117 patients with localized non-Hodgkin's lymphoma (stage I-II). Median age of the patients was 53 years and 52% were men; 22% had a lymphoma of low-grade histology and one-third presented with extranodal involvement. Eighty percent of the patients achieved a complete response (CR); stage of disease and histology were revealed as the most important factors for response. When analysis was restricted to intermediate/high-grade cases, stage showed a predictive value for response. With a median follow-up of 4.5 years, median overall survival was 12.0 years, with 73% and 62.5% of patients being alive at 5 and 10 years, respectively. Main initial parameters significantly related to a shorter survival were intermediate/high-grade histology, stage II, poor performance status, bulky disease, high serum LDH levels, increased ESR, and advanced International Index. In the multivariate analysis, stage, histology and performance status (PS) were statistically significant. Among intermediate/high-grade lymphoma patients, stage and PS provided prognostic value for survival. Twenty-six patients relapsed after CR; median survival after relapse was 2.7 years. Stage (I vs II) was the only predictive variable for relapse in both the whole series and the intermediate/high-grade subset.

Evidence from transgenic mice that myc regulates hepatic glycolysis

The product of the c-myc proto-oncogene (c-Myc) is involved in the control of cell proliferation, differentiation, and apoptosis. It acts as a transcription factor that recognizes the CACGTG motif. This sequence has also been found in the glucose-responsive elements of genes involved in the control of liver glycolysis and lipogenesis. To determine whether c-Myc can regulate hepatic carbohydrate metabolism in vivo, transgenic mice that overexpress c-myc under control of the P-enolpyruvate carboxykinase (PEPCK) gene promoter have been generated. These mice showed a threefold increase in c-Myc protein in liver nuclei. Hepatocytes from transgenic mice were normal and did not acquire the fetal phenotype. However, transgenic mice showed higher levels (threefold) of L-type pyruvate kinase mRNA and enzyme activity than control mice. The increase in pyruvate kinase activity led to a three- to fivefold increase in liver lactate content and a fivefold induction of lactate production by hepatocytes in primary culture. The expression of the 6-phosphofructo-2-kinase gene was also increased in the liver of these transgenic mice. The induction of hepatic glycolysis was related with an increase in the expression (about fourfold) and activity (about threefold) of liver glucokinase, whereas no change was noted in hexokinase-I. This change in glucokinase activity led to an increase in both glucose 6-phosphate and glycogen contents in the liver of transgenic mice. The expression of the liver-specific glucose transporter GLUT2 was also increased in transgenic mice, whereas no change was noted in the mRNA concentration of GLUT1. Furthermore, the changes of liver glucose metabolism led to a marked reduction of blood glucose (25%) and insulin (40%) concentrations in starvation, whereas the fall in both was only 10% in fed mice. Thus, liver glucose metabolism could determine the blood glucose and insulin set points in the transgenic mice. All these results indicated that the increase in c-Myc protein was able to induce liver glucose utilization and accumulation, and suggested that c-Myc transcription factor is involved in the control in vivo of liver carbohydrate metabolism.

Mucosal mantle cell (centrocytic) lymphomas

The morphology, phenotype, genotype and clinical behaviour of four cases of mantle cell lymphoma (centrocytic lymphoma) presenting primarily in mucosa (two gastric, one in large bowel and one tonsillar) are reviewed. Their relationship with the broader group of mantle cell and mucosa-associated lymphoid tissue (MALT) lymphomas is also discussed. All four tumours showed a monomorphic picture of mantle cells (centrocytes) arranged in a diffuse, or vaguely nodular, pattern. Scattered non-neoplastic germinal centres were entrapped within the tumour cells, although there was no follicular colonization. In two cases distinct epithelial infiltration by tumour cells was observed. All four tumours had a CD19, CD20, CD5, IgD, Leu8 immunophenotype, whereas KiM1P and CD10 expression were absent. DRC antibody showed loose aggregates of dendritic cells in three of four cases. Three cases showed PRAD-1/Cyclin D1 overexpression by Northern blot analysis. Although we were not able to detect bcl-1 rearrangement in the major translocation cluster (MTC) breakpoint, the possibility of bcl-1 rearrangement involving other cluster breakpoints cannot be ruled out. The four cases evolved as a disseminated disease, involving either peripheral lymph nodes, spleen or bone marrow. The biological behaviour of mantle cell lymphoma presenting in mucosa appears, irrespective of localization or macroscopic presentation, similar to that of nodal mantle cell lymphoma. Their tendency to dissemination contrasts with MALT lymphomas, which tend to remain localized, and from which mucosa mantle cell lymphoma must be distinguished. The presence of lymphoepithelial lesions does not seem to be a useful differential feature, since occasional epithelial infiltration was seen in two cases. Reactivity with CD5 appears to be especially useful in distinguishing these, since all four cases were clearly positive, in contrast with what is usually found in MALT lymphomas.

Insulin inhibits liver expression of the CCAAT/enhancer-binding protein beta

The CCAAT/enhancer-binding protein beta (C/EBP beta) is a transcription factor that is abundant in the liver. The concentration of C/EBP beta mRNA in the liver of mice and rats fed a high-carbohydrate diet, which causes a rise in blood insulin levels, was lower (80 and 65%, respectively) than that detected in animals fed a standard diet. Similarly, the expression of the human insulin gene in the liver of transgenic mice led to a decrease in the concentration of C/EBP beta mRNA. However, no change was detected in the mRNA levels of C/EBP alpha or cAMP regulatory element-binding protein transcription factors in the livers of these mice. Furthermore, the expression of the C/EBP beta gene increased in the liver of diabetic rats and decreased in the liver of diabetic animals treated with vanadate, an insulin mimetic agent. In addition, a decrease in C/EBP beta protein was observed in liver nuclei from mice after insulin injections, in mice fed a high-carbohydrate diet, and in transgenic mice expressing the insulin gene in the liver. These results suggest that insulin might control gene expression in vivo, at least in part, by a mechanism involving a decrease in the transcription factor C/EBP beta.

[Characteristics of patients with low grade malignant lymphoma and long survival]

PURPOSE

To analyse the initial and evolutive characteristics of the patients with low-grade lymphoma and long survival (> or = 12 years).

MATERIAL AND METHODS

The initial data (clinical, laboratory, histologic type, stage) and the clinical course (response to therapy, response duration) of 52 patients with low-grade lymphoma diagnosed before 1980 were analysed. The statistical study was carried out by means of the chi-square test with Yates' correction and Student's t; the actuarial survival was estimated, and the duration of remission was assessed by the Kaplan and Meier method. Curves were compared by the log rank method.

RESULTS

The 12-year survival as a whole was 32% (CI: 95%: 18.5%-45.5%). Of the 52 patients, 13 (25%) survived over 12 years. Nine were men and 4 women, with median age of 41 years (range: 22-68 years). Three cases had lymphocytic lymphoma and 10 had follicular lymphoma; 2 were in stage I-II and 11 in stage III-IV. Those patients who would become long-survivors had at diagnosis lesser frequency of spread lymph-node regional involvement (> or = 3 sites): 46% vs 81.8%, p = 0.04, as well as lesser percentage of bone-marrow involvement (38.4% vs 78.1%, p = 0.023). They were also better responders to treatment (CR+PR = 100% vs 71%, p = 0.013) and with longer duration (actuarial median duration of response 8 years vs 1.5 years, p = 0.005).

CONCLUSIONS

According to the present analysis, low-grade lymphoma patients who have at diagnosis low tumoral involvement (not too extensive lymph-node involvement, disease-free bone-marrow) and show good response to treatment have a better prognosis and may hope for a longer survival.

Expression of GLUT-2 antisense RNA in beta cells of transgenic mice leads to diabetes

An insulin response to glucose is required to correct hyperglycemia. Two proteins, the glucose transporter GLUT-2 and the glucose-phosphorylating enzyme glucokinase, have been implicated in the control of glucose metabolism in beta cells. To study the role of glucose transporter GLUT-2 in the regulation of insulin secretion and in the development of diabetes mellitus, we have obtained transgenic mice expressing high levels of GLUT-2 antisense RNA in beta cells. Western blot analysis showed an 80% reduction in GLUT-2 protein in the beta cells of these animals. Islets from transgenic mice showed impaired glucose-stimulated insulin secretion. In addition, much higher levels of blood glucose were detected in transgenic mice than in controls when glucose tolerance tests were performed. These results suggest that the reduction of GLUT-2 in the pancreas could be a crucial step in the development of diabetes mellitus.

PRAD-1/cyclin D1 gene overexpression in chronic lymphoproliferative disorders: a highly specific marker of mantle cell lymphoma

The t(11;14)(q13;q32) translocation and its molecular counterpart bcl-1 rearrangement are frequently associated with mantle cell lymphomas (MCLs) and only occasionally with other variants of B-cell lymphoid malignancies. This translocation seems to activate the expression of PRAD-1/cyclin D1 gene located downstream from the major breakpoint cluster region of this rearrangement. However, the possible overexpression of this gene in other lymphoproliferative disorders independently of bcl-1 rearrangement is unknown. We have examined the overexpression of PRAD-1 gene in a large series of 142 lymphoproliferative disorders including 20 MCLs by Northern blot analysis. Cytogenetic and/or bcl-1 rearrangement analysis with 2 probes (MTC, p94PS) were performed in 28 cases. Strong PRAD-1 overexpression was observed in 19 of the 20 MCLs including 3 gastrointestinal forms and 4 blastic variants. t(11;14) and/or bcl-1 rearrangement was detected in 6 of the 12 MCLs examined. No correlation was found between the different levels of mRNA expression and the pathologic characteristics of the lymphoma. Among chronic lymphoproliferative disorders other than MCL, only 1 atypical chronic lymphocytic leukemia (CLL) with a t(11;14) translocation and bcl-1 rearrangement and the 2 hairy cell leukemias (HCLs) analyzed showed upregulation of PRAD-1 gene. The expression in the 2 HCLs was lower than in MCL, and no bcl-1 rearrangement was observed. These findings indicate that PRAD-1 overexpression is a highly sensitive and specific molecular marker of MCL but it may also be upregulated in some B-CLLs and in HCL.

Refractory anemia with excess of blasts and isochromosome 12p in a patient with primary mediastinal germ-cell tumor

Isochromosome(12p), a cytogenetic abnormality characteristic of germ-cell tumors, is exceedingly rare in hematologic disorders. The cytogenetic analysis of a patient diagnosed as refractory anemia with excess of blasts with an associated i(12p), who previously had a teratocarcinoma of the mediastinum, is presented. The cytogenetic analysis was performed at diagnosis of the hematologic malignancy, with all 30 metaphases in the bone marrow culture showing a 47,X, -Y, +8, +i(12)(p10) karyotype. The cytogenetic findings in this patient are compared with those published concerning the association of mediastinal germ-cell tumors and malignant hematologic disorders.

Transgenic mice overexpressing phosphoenolpyruvate carboxykinase develop non-insulin-dependent diabetes mellitus

An increase in hepatic gluconeogenesis is believed to be an important factor responsible for the fasting hyperglycemia detected in patients with non-insulin-dependent diabetes mellitus (NIDDM). Phosphoenolpyruvate carboxykinase (GTP) (PEPCK; EC 4.1.1.32) is a regulatory enzyme of gluconeogenesis. To study the role of the expression of PEPCK gene in the development of NIDDM, we have produced lines of transgenic mice expressing a PEPCK minigene under control of its own promoter. Transgenic mice were hyperglycemic and had higher serum insulin concentrations. In addition, alterations in liver glycogen content and muscle glucose transporter GLUT-4 gene expression were detected. The overexpression of the PEPCK gene led to an increase in glucose production from pyruvate in hepatocytes in primary culture. When intraperitoneal glucose tolerance tests were performed, blood glucose levels were higher than those detected in normal mice. This animal model shows that primary alterations in the rate of liver glucose production may induce insulin resistance and NIDDM.

Low-grade lymphoma: clinical and prognostic studies in a series of 143 patients from a single institution

Clinical and prognostic studies were carried out in a series of 143 patients with low-grade (small-lymphocytic, follicular small cleaved cell, follicular mixed small- and large-cell) lymphoma. After treatment with alkylating agents (21.5% cases), combination chemotherapy (73.3%) or other therapies (5.2%), complete response (CR) was obtained in 40.7% of cases and partial response (PR) in 43.7%. The stage of the disease was the most important factor for response. With a median follow-up of 6.5 years, 48.0% (95% Cl: 37.5-58.5) of patients were alive 10 years after diagnosis. Among the initial parameters, advanced stage. B-symptoms, poor performance status, nodal involvement > 3 sites, extranodal involvement > or = 2 sites, WBC count > or = 10 x 10(9)/L, leukemic expression, high serum LDH levels, and bone marrow infiltration were all related to survival; treatment modality, however, had no influence on survival. In the multivariate analysis, stage (p = 0.008) and age (p = 0.053) were the most important prognostic factors. When considering response to therapy, both CR (p < 0.001) and PR (p = 0.003) emerged as the most important predictive variables, with only the absence of B-symptoms retaining its prognostic significance (p = 0.014) among the other parameters. In addition, in CR patients the duration of the response (< or = 1 year vs. > 1 year) was the most significant parameter for survival (p < 0.001). Finally, the initial stage (p = 0.011) and the histologic subtype (those patients with follicular mixed lymphoma relapsing less frequently than the others) (p = 0.052) were the only significant factors for relapse.

PRAD-1/cyclin D1 gene amplification correlates with messenger RNA overexpression and tumor progression in human laryngeal carcinomas

PRAD-1 is a putative oncogene localized on chromosome 11q13 which encodes cyclin D1, a novel cyclin involved in cell cycle regulation. Amplification of this gene has recently been reported in several human tumors including breast and head and neck carcinomas. In this study we have analyzed the presence of PRAD-1/cyclin D1 gene amplification and mRNA overexpression in a series of 46 matched normal mucosas and squamous cell carcinomas of the larynx. PRAD-1/cyclin D1 was found to be amplified 2- to 12-fold in 17 carcinomas (37%). DNA amplification correlated with advanced local invasion (P = 0.0015), presence of lymph node metastases (P = 0.0078), and stage IV of the tumors (P = 0.0021). mRNA overexpression was found in 15 of the 43 (35%) cases examined and it was also significantly associated with advanced local invasion (P = 0.0025) and stage IV carcinomas (P = 0.0032). A significant association was observed between gene amplification and mRNA overexpression (P < 0.0001) with only 3 discordant cases (2 amplifications with no overexpression and 1 overexpressed carcinoma with no gene amplification). Furthermore, the degree of DNA amplification correlated with the levels of mRNA expression (r = 0.6; P = 0.024). These findings suggest that the PRAD-1/cyclin D1 gene may be an important target of 11q13 amplifications in laryngeal carcinomas and the activation of this gene may be involved in the progression of these tumors. Its association with advanced-stage tumors indicates that PRAD-1/cyclin D1 gene amplification and overexpression may be of prognostic significance.

Impact of response to treatment on survival in multiple myeloma: results in a series of 243 patients

Two hundred and forty-three patients diagnosed with multiple myeloma (MM) in a single institution over a 22-year period and treated with standard chemotherapy were analysed in an attempt to determine the impact of response to therapy on survival. The overall response rate in 229 evaluable patients was 50.1% (34.9% objective response plus 15.2% partial response). Median survivals of patients with objective and partial response were 43.4 and 42.8 months, respectively, versus 19 months for nonresponders. Median survival of 14 patients who achieved a complete remission was 42 months, whereas in 21 rapid responders (< or = 2 months) median survival was 43.3 months. A significant correlation between response and survival was observed with the landmark (P = 0.0169), the Mantel & Byar (P = 0.0001) and the Cox regression model (P < 0.0001) methods. These results indicate that, in responding patients, neither the degree of response nor the response kinetics has a significant influence on survival. However, the response to therapy is associated with a significantly longer survival in MM patients.

Prognostic significance of the loss of heterozygosity of Nm23-H1 and p53 genes in human colorectal carcinomas

BACKGROUND

Nm23 is a gene associated with low tumor metastatic potential and has been proposed to be a metastasis suppressor gene. Nm23 is localized on chromosome 17q21.3-22, whereas the p53 suppressor gene is on 17p13. Allelic deletions of chromosome 17 have been related to the progression of colorectal carcinomas. The purpose of this study was to analyze the allelic deletions of Nm23 and p53 in colorectal carcinomas and to assess their prognostic significance in the evolution of the patients.

METHODS

Allelic deletions of Nm23 and p53 genes were studied in 56 colorectal carcinomas using different restriction fragment length polymorphisms. DNA ploidy and proliferative activity of the tumors were studied by flow cytometry. Actuarial disease free and overall survival were analyzed by the Kaplan--Meier method, and the curves were compared with the log rank test.

RESULTS

Thirty-eight patients were heterozygous for Nm23 gene (68%), and 9 of them (24%) exhibited a loss of heterozygosity in the tumor sample. One of the homozygous patients showed a loss of both Nm23 alleles. Allelic deletions of 17p13 were found in 63% of the 41 informative patients. All patients' tumors that had loss of heterozygosity of the Nm23-H1 locus also had allelic losses on the short arm of chromosome 17 (17p13) and in other loci on 17q. No relationship was found between localization, invasion, lymph node metastasis, or proliferative index of the tumors and the allelic deletions of the Nm23-H1 or 17p13 locus. Nm23-H1 deletions were relatively more frequent in poorly differentiated adenocarcinomas (P = 0.03). A significant association between 17p13 deletions and DNA aneuploidy was found (P = 0.016). A similar tendency was observed with Nm23-H1 deletions (P = 0.051). Loss of Nm23-H1, but not of 17p13, was significantly associated with a shorter disease free (P = 0.025) and overall (P = 0.04) patient survival.

CONCLUSIONS

Allelic deletions of Nm23-H1 are significantly associated with a more aggressive behavior of colorectal carcinomas. The loss of this gene seems to be part of extensive deletions of chromosome 17, and it is also associated with DNA aneuploidy. More studies are needed to determine whether Nm23-H1 or a gene linked to this locus is the specific target of the progression of these tumors.

Applicability of the International Index for aggressive lymphomas to patients with low-grade lymphoma

PURPOSE

Variables used to build up the International Index for aggressive lymphomas (age, performance status, stage, extranodal involvement, and lactic dehydrogenase [LDH]) are also important in low-grade lymphoma. To assess the prognostic value of this index in low-grade lymphoma, we have applied it to a series of 125 patients.

PATIENTS AND METHODS

One hundred twenty-five patients with low-grade lymphoma who were diagnosed at a single institution over a 20-year period and treated with standard chemotherapy were studied. End points of the study were response to therapy and survival according to the International Index. In addition to the International Index, main initial and evolutive variables were evaluated. Univariate and multivariate methods were used.

RESULTS

After applying the International Index, the patients divided into four risk groups: low (36% of cases), low-intermediate (32%), high-intermediate (20.8%), and high (11.2%), with complete response (CR) rates in the four groups being 60%, 35%, 23%, and 21%, respectively. Ten-year overall survival rates for the risk groups were as follows: low, 73.6%; low-intermediate, 45.2%; high-intermediate, 53.5%; and high, 0% (P < .001). When the International Index was included in a multivariate analysis, along with the main initial variables, International Index (P < .001) and sex (male, worse) (P = .038) were the only parameters related to survival. When response to therapy was also included, achievement of CR (P < .0001) and International Index (P < .001) were the most important factors. In patients who achieved a CR, the International Index was the only parameter related to survival (P = .051). The results were the same when the International Index was applied to the subset of 107 patients with follicular lymphoma.

CONCLUSION

In this study, the International Index has been found to be an important prognostic tool in low-grade lymphomas. Such an index could be used to predict prognosis not only in aggressive, but also in low-grade lymphomas.

Prognostic significance of the loss of heterozygosity of Nm23-H1 and p53 genes in human colorectal carcinomas

BACKGROUND

Nm23 is a gene associated with low tumor metastatic potential and has been proposed to be a metastasis suppressor gene. Nm23 is localized on chromosome 17q21.3-22, whereas the p53 suppressor gene is on 17p13. Allelic deletions of chromosome 17 have been related to the progression of colorectal carcinomas. The purpose of this study was to analyze the allelic deletions of Nm23 and p53 in colorectal carcinomas and to assess their prognostic significance in the evolution of the patients.

METHODS

Allelic deletions of Nm23 and p53 genes were studied in 56 colorectal carcinomas using different restriction fragment length polymorphisms. DNA ploidy and proliferative activity of the tumors were studied by flow cytometry. Actuarial disease free and overall survival were analyzed by the Kaplan--Meier method, and the curves were compared with the log rank test.

RESULTS

Thirty-eight patients were heterozygous for Nm23 gene (68%), and 9 of them (24%) exhibited a loss of heterozygosity in the tumor sample. One of the homozygous patients showed a loss of both Nm23 alleles. Allelic deletions of 17p13 were found in 63% of the 41 informative patients. All patients' tumors that had loss of heterozygosity of the Nm23-H1 locus also had allelic losses on the short arm of chromosome 17 (17p13) and in other loci on 17q. No relationship was found between localization, invasion, lymph node metastasis, or proliferative index of the tumors and the allelic deletions of the Nm23-H1 or 17p13 locus. Nm23-H1 deletions were relatively more frequent in poorly differentiated adenocarcinomas (P = 0.03). A significant association between 17p13 deletions and DNA aneuploidy was found (P = 0.016). A similar tendency was observed with Nm23-H1 deletions (P = 0.051). Loss of Nm23-H1, but not of 17p13, was significantly associated with a shorter disease free (P = 0.025) and overall (P = 0.04) patient survival.

CONCLUSIONS

Allelic deletions of Nm23-H1 are significantly associated with a more aggressive behavior of colorectal carcinomas. The loss of this gene seems to be part of extensive deletions of chromosome 17, and it is also associated with DNA aneuploidy. More studies are needed to determine whether Nm23-H1 or a gene linked to this locus is the specific target of the progression of these tumors.

Glucokinase expression in rat hepatoma cells induces glucose uptake and is rate limiting in glucose utilization

In contrast to hepatocytes, hepatoma cells lack glucokinase activity and show increased aerobic glycolysis. FTO-2B and H4IIE rat hepatoma cell lines were obtained in which the rat glucokinase gene was expressed (FTOGK and H4GK). These lines were generated by infection of the hepatoma cells with a retroviral vector carrying the phosphoenolpyruvate carboxykinase (PEPCK)-glucokinase chimeric gene. Both the FTOGK and H4GK cells expressed the chimeric gene in a regulated manner, like the endogenous PEPCK gene. Glucokinase activity was detected in both FTOGK and H4GK. These cells lines showed a marked increase in glucose uptake with 18.5 mM glucose in the incubation medium. FTOGK and H4GK showed an increase in the content of glucose 6-phosphate, and were able to accumulate high levels of glycogen, in contrast to FTO-2B cells, which were unable to store the polysaccharide. In addition, cells expressing glucokinase showed high concentration of fructose 2,6-bisphosphate and substantial lactate production, which was related to the glucose concentration in the medium and the time of incubation. These results suggest that glucose phosphorylation is rate limiting for glucose uptake and utilization in FTO-2B and H4IIE cells.