Early liver metastases in resectable periampullary cancer: Incidence and risk factors.

PURPOSE: The aim of the present study was to estimate the incidence of very early hepatic metastases (HMs) (<6 months) and their imaging patterns after cephalic duodenopancreatectomy (CDP) for periampullary carcinoma (excluding duodenal carcinoma) and to identify their associated risk factors. METHODS: From January 2003 to June 2016, all patients who underwent surgical treatment for periampullary carcinoma by CDP at our institution and with adequate pre- and postoperative CT scans were included. Univariate and multivariate logistic regressions were performed to determine factors associated with very early HM and recurrence. RESULTS: Of the 132 patients included retrospectively, 27 (20.5%) patients developed HMs. The mean time to diagnosis of HM was 103.9±55.2days. HMs were multiple in 81.4% of cases and bilobar in 59.3% of cases; their mean maximum size was 16.7±12.7mm. In univariate logistic analysis, lymphovascular emboli were significantly associated with HM (p=0.02). No independent risk factors for HM were found in multivariate analysis. In multivariate logistic analysis, two independent risk factors were identified for the occurrence of early recurrence: tumor size >23mm on preoperative CT scan (OR: 3.3; 95% CI: [1.2-9.3]; p=0.02) and tumor differentiation (poor vs. good: OR 15.5; 95 CI [1.5-158.3]; moderate vs. good: OR: 17.1; 95% CI: [1.9-154.4]; p=0.04). CONCLUSIONS: Nearly one in five patients developed HM after CDP within 6 months with a highly consistent pattern. A thorough preoperative assessment, combining CT scan and MRI with a delay of less than three weeks before surgery, appears essential. A routine systematic postoperative CT scan at 8 weeks is also required prior to initiating adjuvant chemotherapy. The type of surgical intervention does not seem to be a risk factor, although the risk of HM occurrence appears to be related to the lymphovascular invasion of the tumor and maybe its degree of differentiation, elements not assessable by imaging.

MDCT features of hepatocellular carcinoma (HCC) in non-cirrhotic liver.

PURPOSE: To describe the multidetector row computed tomography (MDCT) imaging features of HCC that develops in patients who are free from underlying liver cirrhosis and to determine if the MDCT presentation of this specific tumor differs from that of the more common HCC that develops in patients with liver cirrhosis using a retrospective case-control study. PATIENTS AND METHODS: The MDCT examinations of 38 patients with HCC in non-cirrhotic liver (group 1) were quantitatively and qualitatively analyzed and compared to those obtained in 38 patients with HCC in cirrhotic liver (group 2) matched for age and gender. Quantitative and qualitative characteristics of HCC of both groups were compared using univariate analysis. RESULTS: HCCs were significantly larger in group 1 (81.5mm±55.5) than in group 2 (44.5mm±39.1 SD; P=0.0015). In group 1, HCCs were more frequently single tumors (87%) than in group 2 (37%) (P<0.0001), encapsulated (92% vs. 47% respectively; P<0.0001), had more frequently fatty component (24% vs. 8%, respectively; P=0.0279) and internal hemorrhage (29% vs. 3%, respectively; P=0.0033). No significant differences were found between the two groups for location, hyperenhancement of HCC during the arterial phase, washout during the portal phase, endoluminal portal involvement by HCC, endoportal cruoric thrombus, invasion of adjacent organs and underlying liver steatosis. CONCLUSION: HCC in non-cirrhotic liver are larger than those observed in cirrhotic liver and more frequently present as a single encapsulated tumor. They have the same patterns of enhancement than HCC that develops in cirrhotic liver.

[Benefit of a short atherosclerosis prevention program on post-stroke vascular risk reduction]. / Intérêt d'un programme court de prise en charge globale de l'athérosclérose sur la réduction du risque vasculaire à distance d'un infarctus cérébral.

INTRODUCTION: Atherosclerosis is a major cause of ischemic stroke. Despite important therapeutic advances, the risk of recurrence of vascular events remains very high. The partial failure of these strategies is to some extent related to the lack of patient adherence to their treatments and to the fact that therapeutic targets are not reached. The aim of the present study was to evaluate the influence of a short atherosclerosis prevention program on vascular risk reduction in stroke patients. PATIENTS AND METHODS: Ninety-five patients with a first ischemic stroke related to atherosclerosis or with a high vascular risk profile were recruited. Three months later, a global evaluation of the atherosclerotic disease and of the vascular risk factors was performed combined with several education sessions on vascular risk factors and way of life. A follow-up evaluation was performed several months later to investigate the number of vascular events and the vascular risk profile. RESULTS: Median follow-up was 684 days after stroke. At follow-up, 91.3% of patients were taking a cholesterol-lowering drug, 95.6% an anti-thrombotic agent, and 78% an angiotensin converting enzyme inhibitor. A persistent decrease in tobacco use and an improvement in glycemic control were observed. During follow-up, 3.2% of patients died; none of the deaths were related to a vascular event. During the 22-month follow-up, 7.6% of patients experienced a major vascular event, acute coronary syndrome or stroke. CONCLUSION: Compared with results in the literature, this study illustrates the positive influence of a short atherosclerosis prevention program combining depiction of atherosclerotic lesions and education of vascular risk factors on the quality of long-term post-stroke prevention.

Early lesions induced in rat colon epithelium by N-methyl-N'-nitro-N-nitrosoguanidine.

The development of ACF (aberrant crypt foci), adenoma and cancer following intrarectal administration of the alkylating agent N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) has been described. However, microscopic lesions not previously reported were observed as soon as two weeks following carcinogen treatment. These lesions protrude slightly over the epithelial lining of the colon, with a micropolyp-like appearance. Oriented sections show that the centre of these lesions present pseudo-"cystic" appearance, with disorganized crypts made of normal cells. The chorion of the lesion is invaded by numerous inflammatory cells and some ACF may be present nearby. The epithelium lining the cysts and the distorted crypts shows expression of gastric mucin M1/MUC5AC, an early marker of colonic carcinogenesis which is not present in normal colon. This mucin is retained within the "cysts" together with some inflammatory cells. The micropolyps observed contain in a minute form some histological elements described in ulcerative colitis or short-term radiotherapy (distortion of crypts, crypt abscesses, increase of chorion cellularity, infiltration by immune cells). In addition, the presence of bifid crypts nearby suggests mucosal regeneration. Our hypothesis is that these modifications are steps in a normal healing pathway that may in some cases degenerate into precancerous lesions and cancer.

Assessing cardiovascular risk factors after coronary artery bypass surgery: value of an aggressive strategy including systematic follow-up.

INTRODUCTION: Coronary revascularization surgery is a palliative treatment modality which should not preclude efforts to treat atherosclerosis. AIM: To assess ongoing cardiovascular risk factors after coronary artery bypass surgery and develop a strategy to attenuate such factors. METHODS: 108 patients requiring a coronary artery bypass were included: 2 died soon after surgery and 6 were excluded for personal reasons. 100 patients were re-admitted into hospital 7 months after surgery for risk factor assessment. Eight months later, they were re-contacted by telephone (systematic follow-up) for a re-assessment. RESULTS: The population consisted of 77 men with an average age of 64+/-11 years. Prior to the operation, the known risk factors were: smoking 34%; HBP 61%; cholesterol 47%; diabetes 30%; obesity 25%. During their hospital stay six months after the procedure: 91% of the patients had at least one lipid metabolism abnormality. New-onset diabetes was diagnosed in 5%. Blood pressure was uncontrolled in 18% and 10% were still smoking. Patients tended to be putting on weight and 55% engaged in little or no physical activity. Systematic follow-up: lipid metabolism had normalized in 70% of the patients. Blood glucose levels were significantly lower. Blood pressure was uncontrolled in 9% and 4% were still smoking. Their weight had stabilized and 65% were engaging in moderate-to-strenuous physical activity. CONCLUSION: Inadequate attention is paid to risk factors after coronary artery bypass surgery. A short hospital stay including a cardiovascular evaluation and education about risk factors has a positive impact on the management of atherosclerosis in the medium term.

Automated function imaging: a new operator-independent strain method for assessing left ventricular function.

BACKGROUND: Speckle tracking is a new technique based on pure 2D grayscale ultrasound acquisition allowing calculation of segmental strains. To facilitate clinical application, speckle tracking has been integrated into the most recent echocardiographic systems for quick, automated evaluation of left ventricular function (Automated Function Imaging, AFI). OBJECTIVE: To evaluate the feasibility, calculation time, accuracy and reproducibility of global longitudinal strain (GLS) from AFI in determining LV function in comparison to reference echocardiographic and angiographic methods-whatever the operator's experience. METHODS: Echocardiography was performed in 65 patients scheduled for cardiac catheterization using a Vivid 7 system. They were divided into 3 groups according to EF (>55%, 35< or =EF< or =55%,<35%). Image quality, global LV function parameters (ejection fraction, aortic flow, dp/dt) and segmental contraction were analyzed by one experienced operator and one beginner. GLS was obtained from apical 2, 3 and 4 chamber views. GLS was compared to both echocardiographic and angiographic EF, as well as to other echocardiographic parameters. RESULTS: GLS was obtained successfully in 97% of patients. Mean calculation time including correction of endocardial detection was less than 60 seconds. GLS was significantly different between the 3 groups, respectively -18.1+/-2.5%, -11.5+/-2.1% and -6.0+/-1.2% (p<0.01). Strong correlations were observed between GLS and LV function (r from 0.68 to 0.87) with a high level of reproducibility. No difference was observed between experienced and inexperienced operators. CONCLUSION: AFI is clinically applicable and an effective means of assessing LV function due to its short acquisition time, feasibility and accuracy, whatever the experience of the operator.

[Echocardiography and biventricular resynchronisation]. / Echocardiographie et resynchronisation biventriculaire.

Biventricular resynchronisation has been recently shown to be an effective therapeutic option in patients with refractory dilated cardiomyopathy. Based on the finding of ventricular asynchrony, the aim of the method is to restore uniform contraction of the ventricular walls. However, the initial electrocardiographic criteria for selection of patients were only associated with a 70% rate of response. Consequently, it became necessary to refocus this method in patients with true ventricular asynchrony. Echocardiography is one of the non-invasive techniques which provides morphological and functional analysis of the myocardium with a high degree of accessibility. The multiplication of tools for echocardiographic quantification has been very valuable from a theoretical point of view for assessing ventricular asynchrony. In practice, techniques such as Doppler tissue imaging are being validated, but already offer the possibility of a multi-directional approach to this pathology. The diagnosis of asynchrony is based on a range of echocardiographic findings which not only improve the selection of patients but also optimise the programming of multisite stimulation.

Mapping of SOMU1 and M1 epitopes on the apomucin encoded by the 5' end of the MUC5AC gene.

We have developed 11 monoclonal antibodies (MAbs) against human gastric mucin, (1-13M1, 2-11M1, 2-12M1, 9-13M1, 58M1, 19M1, 21M1, 45M1, 463M, 589M, 62M1), which specifically stained by immunohistochemisty both the human gastric surface mucosa and colon adenoma. Among them, five (19M1, 21M1, 463M, 589M, 62M1) immunoreacted with the peptide encoded by the 3' region of the MUC5AC gene (Nollet et al: Int J Cancer 2002;99:336-343). In this study, we identified in the 5' region of this gene the nucleotide fragments encoding peptides immunoreacting with three other anti-M1 MAbs (1-13M1, 2-11M1 and 9-13M1), as well as the SOMU1 MAb (Sotozono et al: J Immunol Methods 1996;192:187-196). 1-13M1 MAb immunoreacts with peptides, including the Cys 2 and Cys 4 domains. The SOMU1 MAb recognized the Cys 5 domain, and the MAbs 2-11M1 and 9-13M1 the globular D1/D2 and D3 domains, respectively. Using serial sections of the mucosae adjacent to colon adenocarcinomas and colon adenomas, we observed that the anti-M1 and anti-SOMU1 MAbs displayed the same immunostaining patterns. The three anti-M1 MAbs (2-12M1, 58M1, and 45M1) did not react with the products of the MUC5AC gene tested until now. The MUC5AC apomucin is now well characterized by MAbs immunoreacting against seven different epitopes belonging to the different main cystein globular domains of this macromolecule. Such antibodies are useful tools for studying the biosynthesis, polymerization, and degradation of mucin.

Abnormal expression of gastric mucin in human and rat aberrant crypt foci during colon carcinogenesis.

Colorectal cancer is a major cause of death in Europe and the USA, and much effort is therefore devoted to improve its early detection. In this article, we report the abnormal expression of gastric mucin in aberrant crypt foci (ACF) that appear in the colon mucosae removed from colorectal cancer patients and rats treated with methyl-N'-nitro-N-nitroso-guanidine (MNNG). We performed the immunoperoxidase test using monoclonal antibodies raised against gastric M1 mucin encoded by the MUC5AC gene and against rat gastric mucins (MAb 660), respectively. In both human and rat colon, these anti-gastric mucin MAbs stained specifically goblet cells within ACF. In humans, the M1/MUC5AC mucin was expressed in the upper part of the glands in hyperplastic ACF and in the typical ACF. In addition, the anti-gastric mucin MAbs stained some rare, scattered, histologically normal glands in the human and rat colon mucosae. These glands may be regarded as precursors of ACF. The abnormal expression of the MUC5AC gene constitutes a novel change in addition to genetic modifications already observed in ACF, and supports our previous findings demonstrating the potential of this gastric mucin as an early marker of human and rat colon carcinogenesis.

[Cardiac manifestations of amyloidosis by deposits of transthyretin and apolipoprotein A1. Report of 3 families]. / Manifestations cardiaques de l'amylose par dépôts de transthyrétine et d'apolipoprotéine A1. A propos de 3 cas familiaux.

Amyloidosis is characterised by extracellular deposits of a heterogenous protein. Compared with secondary forms, hereditary amyloidosis due to genetic mutations is rare. The authors report the cardiac manifestations in a French family of 5 sisters and 1 brother, three of whom presented with amyloidosis with deposits of transthyretin and apolipoprotein A1 due to a new genetic mutation.

Gastric M1 mucin, an early oncofetal marker of colon carcinogenesis, is encoded by the MUC5AC gene.

Gastric M1 mucin and the MUC5AC gene show a similar oncofetal expression in the colon. Our aim was to determine whether M1 mucin is the product of the MUC5AC gene. A recombinant baculovirus encoding the C-terminal portion of the MUC5AC gene as a fusion protein was isolated and the immunoreactivity of the recombinant mucin (rM) toward M1 antibodies studied. Chicken antibodies also were raised against purified rM. Besides its reactivity with L56/C, a serum recognizing the bacterially expressed MUC5AC gene product, rM was endowed with M1 immunoreactivity: (i) rM-expressing cells were stained specifically with anti-M1 serum and with the monoclonal antibody (MAb) 21M1, defining the M1-f epitope; (ii) both L56/C and anti-M1 antibodies recognized the same bands in immunoblots of rM-containing cell extracts; (iii) the 21M1 antibody reacted with rM in an immunoradiometric assay. Among the 7 M1 epitopes, M1-f was the only one encoded by the 3' portion of the MUC5AC gene. It was the only epitope detected in a native mucin M1-derived 170 kDa bromelain proteolytic fragment. Furthermore, the staining patterns of human tissues obtained with either anti-rM chicken antibodies or anti-M1 antibodies were identical. We conclude that M1 immunoreactivity is encoded at least in part by the MUC5AC gene.

Detection of gastric mucins (M1 antigens) in cyst fluid for the diagnosis of cystic lesions of the pancreas.

Mucinous cystic tumors of the pancreas must be distinguished from other cystic lesions because of their potential malignancy. Our purpose was to assess the reliability of gastric M1 mucin analysis in the fluid of cystic lesions of the pancreas in comparison or association with carcinoembryonic antigen. M1 mucin and carcinoembryonic antigen were measured in cyst fluid obtained preoperatively by fine-needle aspiration. The lesions consisted of 12 serous cystadenomas, 9 mucinous cystadenomas, 8 cystadenocarcinomas and 6 intraductal mucinous hypersecreting neoplasms. Thirty pancreatic pseudocysts complicating well-documented chronic pancreatitis were also examined. In addition, M1 mucins were localized by immunoperoxidase staining in fetal and normal adult pancreas and in mucinous and serous tumors. Carcinoembryonic values of > 20 ng/ml and M1 mucin values of > 50 U M1/ml represented 82 and 78% sensitivity, respectively, as well as 100% specificity for distinguishing mucinous lesions from serous cystadenomas; the sensitivity for this purpose was 100% using these criteria in combination. Carcinoembryonic antigen values of > 300 ng/ml and M1 mucin values of > 1,200 U M1/ml represented 56 and 30% sensitivity, respectively, as well as 100% specificity for distinguishing mucinous lesions from pseudocysts; the sensitivity for this purpose was 60% using these criteria in combination. By immunohistology, M1 mucins were detected in the wall of mucinous lesions but not in fetal and normal adult pancreas and in serous cystadenomas. Measurement of M1 mucin antigen in cyst fluid could thus improve the diagnosis of mucinous cystic lesions of the pancreas.

Enterocyte differentiation is compatible with SV40 large T expression and loss of p53 function in human colonic Caco-2 cells. Status of the pRb1 and pRb2 tumor suppressor gene products.

Transfer of the SV40 large-T (LT) oncogene into isolated human and murine intestinal epithelial cells induced alterations of the ultrastructural organization and polarization of the resulting immortalized cell lines. We now demonstrate that the functional expression of the SV40 LT antigen in Caco-2 cells did not alter phenotypic markers of differentiation, including expression of villin, sucrase-isomaltase, brush border and dome formation. As compared to parental cells, the transfected Caco-2 LT9 cells exhibited similar growth curves and no invasive properties in vitro. The major oncogenic function of the SV40 LT antigen in transfected Caco-2 cells is associated with reduced latency times necessary for the manifestation of tumors in athymic nude mice. The Caco-2 cell line contained deleted and mutant p53 alleles (stop codon in position 204) and has no detectable truncated p53 protein by Western blot. Molecular complexes between the SV40 LT antigen and the retinoblastoma-related proteins pRb1 and Rb2 were clearly identified at the different phases of the growth curve. When compared to normal human colonic crypts, Caco-2 cell differentiation is related to partial redistribution of pRb1 into hypophosphorylated, antiproliferative forms. The pRb2 protein is found elevated in a subset of human colorectal tumors and their corresponding liver metastases. We conclude that: (1) Caco-2 cells exert a dominant control against the oncogenic functions of the LT antigen; (2) loss of p53 function is not restrictive for the establishment of polarity and differentiation of the enterocyte lineage; (3) the levels and phosphorylation status of the Rb1 and Rb2 proteins may play important roles in the proliferation and differentiation of normal and neoplastic human colonic mucosa.

Devazepide (L-364718) inhibits growth and increases expression of tumor markers in HT29-S-B6 cells.

Devazepide (L-364718, a non-peptide antagonist of CCK-A receptors), inhibits the proliferation and induces morphologic changes in the mucous-secreting, autonomously proliferating human cancer colon cell line (HT29-S-B6. Addition of devazepide (10 microM) for at least 3 days in the exponential phase of growth enhanced the baseline production of gastric M1 mucins 2-3-fold and that of carcinoembryonic antigens 5-fold. Moreover, devazepide induced an increase in the amount of the MUC-5AC mRNA expressed by HT29-S-B6 cells. The increased in mucins secretion induced by devazepide was persistent after removal and independent of the presence of serum. In conclusion, devazepide-L-364718 behaves as a maturation agent in the cell clone HT29-S-B6.

Antiproliferative effects of the arotinoid Ro 40-8757 in human gastrointestinal and pancreatic cancer cell lines: combinations with 5-fluorouracil and interferon-alpha.

The arotinoid Ro 40-8757 was previously shown to inhibit the growth of a variety of human cancer cell lines derived from breast, lung and uterus. In view of the high incidence of human digestive cancers, and the slow progress in the development of new therapy, we examined in this paper several combinations between the new arotinoid Ro 40-8757, 5-fluorouracil (5FU) and interferon alpha-2a on the growth of nine human cancer cell lines derived from the gastrointestinal and pancreatic system. Half-maximal inhibition of cell proliferation by Ro 40-8757 was observed at concentrations ranging between 0.18 and 0.57 microM, and increased up to 4.7 microM in retinoid-resistant CAPAN 620 pancreatic cells. All-trans-retinoic acid was 70 times less potent. The sensitivity of HT29-5FU-resistant colonic cells was similar to that observed in the parental cells, suggesting an action independent of pyrimidine metabolism. Ro 40-8757 did not induce any differentiation on HT29 cells, as suggested by ultrastructural analysis. The arotinoid did not interact with receptor signal transduction pathways under the control of serum components, such as growth factors as half-maximal inhibiton of growth was similar in HT29-S-B6 cells cultured in the absence or presence of serum. Cell cycle analysis showed that Ro 40-8757 was not acting at a phase-specific transition in HT29 cells and, accordingly, did not induce overexpression of the protein kinase C (PKC)alpha isoform, or conversion of hyperphosphorylated p105 Rb into hypophosphorylated forms. However, the arotinoid induced significant accumulation of the dephosphorylated, active form of the tumour-suppressor protein. Combinations of Ro 40-8757 with 5FU and interferon alpha 2a resulted in an additive but not synergistic antiproliferative action in HT29 cells. Our data support the interest in Ro 40-8757 as a potent anti-cancer drug, especially in combination therapy with 5FU and interferon, in gastrointestinal and pancreatic cancers, where new active therapeutic modalities are urgently needed.

Effects of VIP on the regulation of mucin secretion in cultured human pancreatic cancer cells (Capan-1).

The effects of Vasoactive intestinal peptide (VIP) on mucin secretion in the pancreatic cancer Capan-1 cell line were studied by Enzyme-linked-immunosorbent-assay (ELISA), and by light and electron microscopy using immunocytological methods. During the exponential growth phase, mucins were accumulated in the cytoplasm of cells and slowly exocytosed. In contrast, there was enhanced exocytosis of mucins during the stationary phase when the cells were well-polarized. Moreover, during this phase, VIP induced a dose-dependent rise in mucin content in the extracellular medium. The reaction with anti-M1 monoclonal antibodies, which recognize specifically the peptide core of gastric mucins, showed an accumulation of secretion granules near the apex of well-polarized cells together with fusion of the granule and plasma membranes after VIP stimulation. Moreover, mucin exocytosis was stimulated by Pituitary adenylate cyclase activating polypeptide (PACAP) and secretin. It was also increased after forskolin treatment suggesting that this mechanism was cAMP-dependent. Our results suggested that exocytosis of mucins could be under the control of VIP in pancreatic duct cells of the Capan-1 cell line.

Effects of ketoconazole on the proliferation and cell cycle of human cancer cell lines.

The growth-inhibitory effects of ketoconazole, an antifungal agent which inhibits arachidonic acid lipoxygenases and cytochrome P-450 enzymes, were tested in human colon and breast cancer cell lines. In the serum independent HT29-S-B6 colon cell clone, ketoconazole reduced cell proliferation and [3H]thymidine incorporation in a dose-dependent fashion, with a 50% inhibitory concentration of approximately 2.5 microM. Flow cytometry showed an accumulation of cells in the G0-G1 phase of the cell cycle and a concomitant decrease of the percentage of cells in S phase. Ketoconazole also inhibited [3H]thymidine incorporation in the hormone-independent breast cancer cells MDA-MB-231 and Evsa-T, with respective 50% inhibitory concentration of approximately 13 and 2 microM. The mechanism of action of ketoconazole is unknown. However, another lipoxygenase inhibitor, BW755C, inhibited only weakly [3H]-thymidine incorporation and accumulated the cells in S and G2. Conversely, clotrimazole and SKF525A, inhibitors of cytochrome P-450 enzymes, had effects similar to those of ketoconazole on HT29-S-B6 cells whereas metronidazole and secnidazole, other azole derivatives which do not inhibit cytochrome P-450 enzymes, had no effect. The results suggest that cytochrome P-450 enzyme(s) activity(ies) could be implicated in the antiproliferative effects of ketoconazole.

Proliferation of the human colon carcinoma cell line HT29: autocrine growth and deregulated expression of the c-myc oncogene.

Human colon adenocarcinoma cell (line HT29) are able to proliferate in a defined (serum-free) medium containing no added growth factors; in such conditions, their doubling time is 3 to 4 days (on serum-coated dishes) or 2 to 3 days (on an autologous extracellular matrix) compared with 1 day in the presence of fetal calf serum. In the presence of suramin, a polyanion disrupting the binding of growth factors to their receptors, the incorporation of [3H]thymidine in serum-free cultures is reduced (27.0 +/- 2.9% of control after 3 days of culture), suggesting involvement of autocrine growth factors in the autonomous proliferation of the cells. The expression of the proliferation-related oncogene c-myc was examined during various stages of growth and differentiation of the HT29 cells. The cellular contents of c-myc mRNA were similar in all experimental conditions studied: exponential phase; stationary phase; nondifferentiated as well as differentiated cells (by glucose deprivation); and also in serum-free medium containing or not suramin. An approximately 2-fold increase in the level of c-myc mRNA was observed in cells cultured for 3 days in suramin-containing medium and then incubated during 3 h in the absence of suramin (with or without 10% fetal calf serum). Southern blot analysis of the genomic DNA of HT29 cells did not reveal any rearrangement within the region containing the c-myc gene and the flanking sequences (approximately five kilobases upstream and approximately three kilobases downstream). The c-myc locus was weakly amplified (four to six copies per cell). These results indicate that the c-myc gene expression in HT29 cells is deregulated and does not require growth factor stimulation. The deregulation of the c-myc gene may be related to the reduced growth factor requirement of the HT29 cell line.