Analysis of microRNA expression in brush cytology specimens improves the diagnosis of pancreatobiliary cancer.

BACKGROUND/OBJECTIVES: Malignant pancreatobiliary strictures are in many cases clinically indistinguishable and present a major problem to endoscopy specialists. Intraductal sampling procedures such as brush cytology are commonly used for diagnosis with a sensitivity that is low for a diagnostic test used in daily clinical practice. MicroRNA (miR) alterations detected in many cancers are disease-specific, which can be utilized in clinical applications. The aim of the present study was to analyze whether determination of miR expression levels in intraductal brush cytology specimens is a feasible approach to improve the diagnosis of pancreatobiliary cancer. METHODS: Brush cytology specimens have been collected during endoscopic retrograde cholangio-pancreatography (ERCP) and analyzed by routine cytology and ancillary miR assays. Total RNA was extracted using the miRNeasy Mini Kit and the expression of miRs frequently dysregulated in pancreatobiliary cancer (miR-16, miR-21, miR-196a, miR-221) were analyzed by quantitative real-time PCR using RNU6B as internal control. RESULTS: Routine cytology resulted in no false positive diagnoses, however, the combined sensitivity remained at 53.8%. Expression (ΔCt values) of miR-16 (p = 0.0039), miR-196a (p = 0.0003) and miR-221 (p = 0.0049) showed a clear statistical significance between malignant and benign pancreatobiliary specimens (n = 35). Malignancy could be detected combining routine cytology and the miR-196a single marker expression levels with a sensitivity of 84.6% (92.9% in biliary strictures) with no false positives. CONCLUSIONS: The results offer the first direct demonstration that microRNAs are readily detectable in brush cytology specimens obtained during ERCP, and have the potential to help the cytological diagnosis of pancreatobiliary malignancy.

Continuous administration of the somatostatin structural derivative /TT-232/ by subcutaneously implanted osmotic pump improves the efficacy and potency of antitumor therapy in different mouse and human tumor models.

BACKGROUND: The somatostatin structural derivative, TT-232, has a special 5-residue ring structure (D-Phe-Cys-Tyr-D-Trp-Lys-Cys-Thr-NH2) and very different characteristics from the known growth hormone (GH) active somatostatin analogs. This somatostatin structural derivative has no GH release inhibitory or antisecretory activity and does not bind to rat pituitary or the cortex, where all the known somatostatin receptor subtypes are expressed. TT-232 had previously been shown to inhibit the proliferation of a large number of cancer cell lines in vitro and reduce the size of different tumors in animal models in vivo. MATERIALS AND METHODS: The therapeutic efficacy of TT-232 was evaluated in different long-term administration routes: the traditional injection (i.p. or s.c.) versus infusion treatment via s.c.- or i.v.-inserted Alzet osmotic minipump, and on different types of transplantable rodent (S-180 sarcoma, P-388sc lymphoid leukemia, Colon-26 adenocarcinoma, MXT breast carcinoma, B-16 melanoma) and human tumor models (HT-18 lymphoid melanoma, T-47/D breast carcinoma, A-431 epidermoid carcinoma). On the basis of our previous experiments the optimum injected dose of TT-232 was found to be 15 microg/kg twice a day. This dose is equivalent to 0.6 dg/day by infusion therapy. RESULTS: In our experiments, the best results were achieved when TT-232 was applied as an infused treatment. In the S-180 sarcoma and P-388sc lymphoid leukemia rodent tumor models the infusion treatment with TT-232 resulted in 61%-100% tumor growth inhibition and in 20%-60% of the mice being long-term and tumor-free survivors. In the aggressive Colon-26 adenocarcinoma and MXT breast carcinoma models, the infusion treatment resulted in 52%-75% tumor growth inhibition. In the B-16 melanoma model, the infusion treatments resulted in 47% -63% growth inhibition. The tumor growth inhibitory effect of infusion treatment with TT-232 on HT-18 human lymphoid melanoma tumor proved to be significant, resulting in 69%-79% decreases in tumor volume. In the T-47/D human breast carcinoma, the infusion treatment resulted in 48%-53% tumor growth inhibition. The tumor growth inhibitory effect of infusion treatment on A-431 human epidermoid carcinoma tumor resulted in 70%-74% decreases in tumor volume. CONCLUSION: The antitumor efficacy of TT-232 was seen in almost all the tumors investigated. In our study, the route of infusion was shown to increase drug efficacy relative to conventional delivery methods (injection). The results obtained from this study suggest that TT-232 is a promising new antitumor agent in cancer chemotherapy and a good candidate for delivery by continuous (infusion) therapy.

A comparison of the tumor growth inhibitory effect of intermittent and continuous administration of the somatostatin structural derivative TT-232 in various human tumor models.

The tumor growth inhibitory efficacy of the somatostatin structural derivative TT-232 was studied using different routes of administration and treatment schedules in various human tumor models. TT-232, containing a five-residue ring structure, has a strong antitumor activity both in vitro and in vivo. The antineoplastic activity of TT-232 has been found to be associated with the induction of programmed cell death in tumor cells, resulting in highly-selective elimination of the neoplastic tissue. The study compared the antitumor efficacy of TT-232 in various long-term administration routes; the intermittent (injection) versus continuous (infusion) treatment via subcutaneously-inserted Alzet osmotic minipumps in different human tumor models: T-47/D human breast carcinoma and A-431 human epidermoid carcinoma. Treatment with TT-232 started after disease development. The antitumor activity of TT-232 was evaluated on the basis of the tumor growth inhibition. In the case of T-47/D human breast carcinoma, the intermittent treatment resulted in 23%-26% and the infusion treatment resulted in 48%-53% tumor growth inhibition. The tumor growth inhibitory effect of TT-232 on A-431 human epidermoid carcinoma tumor resulted in 35%-43% (intermittent treatment) and 70%-74% (continuous treatment) decreases in tumor volume. This antitumor efficacy of TT-232 was observed in the two human tumors investigated. In this study, the route of infusion was shown to increase drug efficacy relative to conventional delivery methods. The results suggest that TT-232 is an effective and promising antitumor agent.

Epidermal growth factor increases 32P incorporation into phosphatidylcholine and protein kinase C activity in colon carcinoma cell line (HT29).

There are conflicting data about the effect of the epidermal growth factor (EGF) on protein kinase C (PKC) enzyme activity. The aim of our study was to find out which type of phospholipids [phosphatidylinositol 4,5-bisphosphate PI4,5P2 or the other phospholipids-phosphatidylcholine (PC) or phosphatidic acid (PA)] could be the source of 1,2-diacylglycerol (1,2-DAG) in PKC activation. In colon carcinoma cells (HT29) we observed a more than 2-fold increase in the PC pool and at the same time decreased tyrosine kinase activity (50%). With increasing incubation time EGF affects the pools of both phosphatidylinositols and other phospholipids parallel with the activation of the tyrosine kinase activity. EGF increases the activity of PKC in the HT29 cell line and PC could be the source of 1,2-DAG which may stimulate PKC activity.

Phosphatidylcholine could be the source of 1,2-DAG which activates protein kinase C in EGF-stimulated colon carcinoma cells (HT29).

In our previous study (A. Balogh et al, Cell. Signalling 5 (6), 795-802, 1993.), we have shown that epidermal growth factor (EGF) increased protein kinase C (PKC) activities in colon carcinoma cell line (HT29), possibly through the increased 1,2-diacylglycerol (1,2-DAG) production via phosphatidylcholine (PC). Here we investigate the effect of well-known PKC activator 12-O-tetradecanoyl-2 phorbol-13-acetate (TPA), on the levels of 32P incorporation into EGF induced phosphatidylinositols (PI, PI4P, PI4, 5P2) and different phospholipids (PC, PA, PS) as well as on induced tyrosine kinase activity. TPA significantly decreased the effects of EGF and it had the biggest inhibitory effect on EGF induced PC level. These data support our contention that PC plays an important role in the activation of PKC via 1,2-DAG production in the EGF stimulated pathway.

Growth inhibitory effect of the somatostatin structural derivative (TT-232) on leukemia models.

TT-232 is a structural derivative of the natural signal inhibitory peptide somatostatin, with selective antiproliferative and anti-inflammatory properties. TT-232 activates SSTR receptors (primarily the SSTR-1), which leads to irreversible cell cycle arrest, followed by secondary induction of apoptosis. TT-232 has passed phase I clinical trials without toxicity and significant side-effects. We examined the antiproliferative effect in vitro and the antitumor effect in vivo of TT-232 on leukemia cell lines. During in vivo experiments, we evaluated the therapeutic efficacy of TT-232 in various long-term administration routes; traditional injection versus infusion treatment via an inserted Alzet minipump on P-388 mice and HL-60 human leukemia models. Treatment with TT-232 started after development of the disease. In vitro, TT-232 inhibited the proliferation of P-388 mice lymphoid cells and HL-60 human promyelocytic leukemia cells in the range of 46%-97% with 24-hour treatment and 82%-100% with 48-hour treatment. Cells were treated with 30 microg/ml and 60 microg/ml dose of TT-232. With the same in vivo models, the best results were achieved when TT-232 was applied by infusion treatments. The infusion treatment with TT-232 produced 50%-80% inhibition of growth and resulted in 20%-40% long-term and leukemia-free survivors. TT-232 showed dose-, time- and administration mode-dependent antileukemia activity in vitro and in vivo, both on rodent and human models. Our results suggest that TT-232 is a promising new antileukemia agent.

In vitro search for synergy between flavonoids and epirubicin on multidrug-resistant cancer cells.

The drug accumulation of a human multidrug resistance 1 (mdr1) gene-transfected mouse lymphoma cell line and a multidrug resistance protein (MRP)-expressing human breast cancer cell line MDA-MB-231 was compared in the presence of sixteen flavonoids and five isoflavonoids. The expression of the 170-kDa P-glycoprotein (P-gp) (MDR1) and 190-kDa multidrug resistance protein (MRP) in both cell lines was confirmed by immunocytochemistry. The rhodamine 123 accumulation of the P-glycoprotein (P-gp)-expressing cells increased up to 46.4, while 2,7'-bis(2-carboxyethyl)-5(6)-carboxy-fluorescein acetoxymethyl ester (BCECF-AM) accumulation of the MRP-expressing cells increased up to 1.6, in fluorescence activity ratio (FAR). Major P-gp-mediated efflux pump modifiers are formononetin, amorphigenin, rotenone and chrysin, while MRP-mediated efflux pump modifiers are formononetin, afrormosin, robinin, kaempferol and epigallocatechin. In antiproliferative assay, afrormosin, amorphigenin, chrysin and rotenone exhibited the strongest antiproliferative effects in L5178 (max. ID50: 19.70) and MDA-MB-231 cell lines (max. ID50: 55.47). In a checkerboard microplate method in vitro, furthermore, the most effective multidrug resistance (MDR) resistance modifiers, amorphigenin, formononetin, rotenone and chrysin, were assayed for their antiproliferative effects in combination with epirubicin. Rotenone and afrormosin showed additive effects. Chrysin and amorphigenin on the mouse lymphoma cell line and formononetin on the MDA-MB-231 cell line synergistically enhanced the effect of epirubicin.

Experimental and clinicopathologic studies on the function of the HGF receptor in human colon cancer metastasis.

The organ-specific metastasis characterizes several human cancers, including colon carcinoma, a disease that frequently involves metastases in the liver. The data on the molecular mechanisms of liver metastasis would therefore be highly useful for prognostic purposes. Although the upregulation/amplification of the hepatocyte growth factor (HGF) receptor, c-met, has been frequently observed in colon cancer metastasis, the actual functional significance of the feature in the liver metastatization is not yet known. We have used three human colon carcinoma cell lines (HT29, HT25 and WiDr), characterized by different liver metastatic potentials in SCID mice, to analyze the expression of c-met and the biological effects of HGF. We found that HGF induces scattering in in vitro liver-metastatic cell lines (HT25 and WiDr) only at doses which are non-mitogenic (1-20 ng/ml). Analysis of the c-met expression revealed that the metastatic cell lines express authentic c-met gene and protein material, unlike the non-metastatic HT29 cell line, which expresses only the c-terminal cytoplasmic domain of the c-met beta-chain. Interestingly, c-met was found to be localized in the substrate-attached peripheral membrane and partially colocalized with phosphotyrosine-proteins in the metastatic cells only when kept on fibronectin. On the other hand, we have analyzed 86 primary human colon cancers in Dukes' B (invasive but non-metastatic) and C (invasive and lymph node metastatic) stages. Western blotting of the proteins isolated from the tumor tissues and immunohistochemical control study on the paraffin samples of a third of these cases (25/86) all indicated a significant upregulation of the c-met protein in the Dukes' C tumor glands compared to the Dukes' B stages (P < 0.001 and P < 0.05, respectively). Since the two stages differ in the involvement of the regional lymph nodes but not in the invasion depth, the clinicopathological data and our experimental findings further support the notion that the c-met expression in human colon cancer can be considered as a marker of the metastatic potential due to its involvement in the generation of the motility signal.

Modulation of cytosine arabinoside-induced proliferation inhibition by exogenous adenosylmethionine.

The effect of cytosine arabinoside on adenosylmethionine synthesis in relation to its proliferation-inhibiting ability was investigated in HT/29 and SW 620 human colon-tumor cell lines. A significant decrease in adenosylmethionine synthetase (E. C.2.4.2.13) activity was found after 2.5 h incubation with the drug, suggesting that depletion of adenosylmethionine pools might occur. Both this possible loss of adenosylmethionine and the cytostatic effect of cytosine arabinoside could partly be reversed by the exogenous administration of the former drug. Our data show that the cytostatic effect of cytosine arabinoside may be due in part to a shortage of adenosylmethionine; this finding is important for the design of combination chemotherapy regimens.

The antitumor activity of the somatostatin structural derivative (TT-232) on different human tumor xenografts.

A somatostatin structural derivative (TT-232) has been developed in our laboratory with strong antiproliferative effect but no GH- release inhibitory activity. TT-232 inhibited tyrosine kinase activity of tumor cells lines and this inhibition correlated well with the inhibition of cell proliferation. The antineoplastic activity of TT-232 has been found to be associated with induction of programmed cell death (apoptosis) in tumor cell, resulting in highly selective elimination of neoplastic tissue. The aim of this study was the therapeutic efficacy of TT-232 on different human models: PC-3 prostate carcinoma, MDA-MB-231 (ER-) and MCF-7 (ER+) breast carcinoma, HT-29 colon carcinoma, HT-18 melanoma, HL-60 promyelocytic leukemia. We studied the therapeutic efficacy of the novel somatostatin analog, it for 30 days with intermittent injection once daily and for 14 days with s.c. infusion using the Alzet osmotic minipump (model 2002). The antitumor activity of TT-232 was evaluated on the basis of survival time and tumor growth inhibition. The tumor growth inhibitory effect of TT-232 on human tumor xenografts proved to be significant, resulting in 30%-80% decrease in tumor volume and in 20-60% tumor free animals. This antitumor efficacy of the novel somatostatin analog was observable in almost all tumors investigated. These data suggest that the novel somatostatin analog (TT-232) is an effective and promising antitumor agent.

Correlation of biochemical tumor markers with conventional pathological features in primary breast cancer.

In this prospective study the correlation of pathological with biological prognostic factors and serum tumor markers has been investigated in 574 patients with primary invasive breast cancer. The p53 protein and Bax level correlated positively with tumor size, lymph node status and histological grade. The serum levels of CEA, CA 15.3, TPA-M and TK correlated with tumor extent. There was a significant difference between pre- and postmenopausal breast cancer patients in serum levels of TPA-M and cytosol levels of Bax. Whether these correlations can help in predicting the prognosis of breast cancer by providing additional information with respect to the conventional factors, will have to be investigated by several years of careful clinical follow-up.

Predictive value of p53, Bcl2 and bax in the radiotherapy of head and neck cancer.

Radiation is known to induce DNA damage resulting in the onset of apoptosis. The apoptosis is modulated by p53, Bcl2 and Bax proteins. High level of wild type p53 is required for radiation induced apoptosis. The p53 status, therefore, may be a crucial determinant of radiosensitivity of tumor cells. Overexpression of Bcl2, however, inhibits apoptosis via hetero- and homodimeric interaction. Bax might function as a cell death effector molecule that is neutralized by Bcl2. The aim of the present study is to investigate the correlation between p53, Bcl2, Bax and c-myc levels and the clinical response of head and neck cancer patients to radiation. The base line and 30 GY gamma radiation induced values of p53, Bcl2, Bax and c-myc were estimated by Western blot in 40 biopsies of head and neck cancers. We found that the radiosensitivity of head and neck cancer patients depends on the ratio of p53, Bcl2 and Bax protein levels. High Bcl2 levels resulted in radioresistance of cancer patients. Overexpression of Bax and c-myc may ensure the radiosensitivity of head and neck cancer patients. Our studies indicate that prediction of radiation sensitivity of tumors could be based on the simultaneous evaluation of p53, Bax and Bcl2 levels.

Molecular pathology of tumor metastasis. I. Predictive pathology.

Millennium reviews of oncology agreed that the last century produced major developments mainly in the management of the primary tumor, but despite all of these results, cancer still remains among the leading causes of death due to the failure of clinical management of disseminated disease. This failure is primarily due to the lack of detailed information on the molecular mechanisms of tumor metastasis. Therefore, one of the hottest fields in experimental oncology is metastasis research, which provides more and more information about the molecular mechanisms. However, this information is fragmented and is not yet exploited in clinical practice. A new field of diagnostic pathology recently emerged, which translates basic research data to diagnostic practice to provide clinically relevant information on the biological potential (in this case metastatic potential) of the malignant tumors. Since tumor cell-extracellular matrix interactions are key features of tumor dissemination, expression of genes responsible for them can define the metastatic potential of malignant tumors. This review summarizes our recent knowledge on the metastatic geno- and phenotype of major human solid tumors: lung, colon, breast, prostate cancers and malignant melanoma.

[Low-dose Taxol radiosensitization in locally advanced head and neck cancers] / Alacsony dózisú Taxol-sugárérzékenyítés helyileg elôrehaladott fej-nyaki daganatokban.

INTRODUCTION: Combined modality treatment with chemotherapy and radiotherapy in locally advanced head and neck cancers is an effective and often the only treatment with a chance of cure. An alternative is to use chemotherapeutic agents at low doses as radiosensitizers. In this study we examined the radiosensitizing effect of low dose Taxol in locally advanced head and neck cancer. Patients and methods: 26 patients with locally advanced squamous cell carcinoma of the oral cavity and the oropharynx were treated with external beam radiotherapy up to doses of 66-70 Gy and received concomitantly 2 mg/m(2) Taxol intravenously three times a week. Response rates according to WHO criteria, side effects according to the National Cancer Institute Common Toxicity Criteria, overall and progression-free survival were evaluated. RESULTS: All patients completed the therapy. Median radiation dose was 66 Gy, Taxol dose 40 mg/m(2) and treatment duration 54 days. 8 weeks after completion of therapy complete response was 30.8%, partial response 34.6%, stable disease 11.5% and progressive disease 23.1%. The median follow-up time was 25 months (9-36). At the cloes- out date 12 (46,1%) of the patients were alive, 9 without evidence of disease. The estimated median overall survival was 22 months (CI 14.2-34.6), the median progression-free survival 12 months (CI 5.2-18.8). We observed four grade 4, fourteen grade 3 and numerous grade 1-2 side effects. There was no treatment related death. DISCUSSION: Our regimen resulted in a worse response rate than the aggressive chemoradiation protocols treating the same disease. However, the two-year survival was comparable with the results of other studies. The advantages of our schedule are that it is well tolerated, easy to perform on an outpatient basis, resource effective and does not deteriorate the general condition of the patients, therefore successive therapy can be carried out immediately if necessary. We intend to evaluate the effectivity of this treatment in a study comparing radiotherapy with Taxol sensitization versus radiotherapy alone.

[Combined modality treatment of locally advanced oral and oropharyngeal cancer following primary radiotherapy with and without taxol radiosenzitization] / Komplex onkoterápia eredményei elôrehaladott stádiumú fej-nyaki laphámrákos betegek Taxol-sugárérzékenyítéssel és anélkül végzett primer sugárkezelését követôen.

AIM: To determine the effect of radiosensitization with Taxol and multimodality treatments on the survival of advanced oral and oropharyngeal cancer. Patients, methods: 56 patients with St. III-IV oral or oropharyngeal cancer were treated with external beam radiotherapy; 26 of them were sensitized by low-dose paxlitaxel and 30 were irradiated traditionally. The median follow up was 23 months (17-36). Endpoints of the study were: response to radiotherapy, progression-free and overall survival and the results of surgery and chemotherapy following radiation. RESULTS: 73.3% (41/56) of treatments resulted in CR or PR with median 10 months (0-33) progression-free and 14 months (4-33) overall survival. There was no significant difference between the radiosensitized and traditional radiotherapy group (p=0.6). The survival was significantly influenced by the stage of tumor and the response to primary radiotherapy. Seven (38.9%) of 16 patients treated also by either surgery or chemotherapy for recurrent or residual disease are free of cancer, 6 (35%) alive with tumor and 5 (26.1%) died with median survivals of 21, 20.5 and 18 months, respectively. Those treated only with radiotherapy with or without sensitization are free of cancer in 31.6%, alive with cancer 5.3%, died 63.2%. CONCLUSION: There were significant correlation between tumor stage, response to radiotherapy and combined modality treatment, and surival. The radiosensitizing effect of Taxol was not obvious so far, it may be apparent in the future by analyzing the long term survival data.

[Genetic marker analysis in head and neck cancer] / Genetikai marker-vizsgálatok fej-nyaki daganatokban.

Prognostication of head and neck cancer (HNCC) involves molecular identification of residual tumor cells, prediction of recurrence, distant metastases or secondary tumors and prediction of the sensitvity to therapy. Biomarkers of HNCC are mutations of p53, p16 and amplification of Cyclin D and E2F4. One hundred and fifty-two HNCC cases have been evaluated for p53, hMLH1, Cyclin D and p16 gene alterations using PCR-SSCP and Western blot analysis. P53 mutations of HNCC have been found in 37.5% of cases. However, 11% of the cases showed p53 mutations in the normal peritumoral mucosa suggesting "field cancerization" process. Mismatch-repair gene mutations (MMR: hMHL1 and hMSH2) occurred with 17 and 8.6% frequency, respectively, while E2F4 mutations were even more frequent (21.4%) in HNCC. Our data suggest that E2F4 overexpression can be caused by the inactivation of the p16 gene in HNCC, while its mutations are most probably associated to the mutations of the MMR genes. These molecular informations can help to predict the biological potential of HNCC as well as the probability of the development of secondary HNCCs.

MLH1 and MSH2 mutation screening in HNPCC families of Hungary - Two new MMR gene mutations.

INTRODUCTION: Hereditary Non-Polyposis Colorectal Cancer is an inherited disease with deleterious germline mutations in the DNA mismatch repair genes causing the development of colon cancer and other malignancies. This is the first study in Hungary screening the population of our colorectal cancer patients in order to identify the prevalence of the disease. METHODS: In families who met the Modified Amsterdam and Bethesda Criteria the removed tumor tissue was first examined by immunohistochemistry and microsatellite instability analysis. Those cases which showed high microsatellite instability underwent DNA sequencing and multiple ligation dependent probe amplification. RESULTS: Of the 1576 patients with colorectal cancer underwent screening for the modified Amsterdam and Bethesda criteria, 69 (4.4%) and 166 (10.5%) fulfilled the criteria respectively. 15 patients (31%) of the Amsterdam positive group and 19 patients from the Bethesda positive (18.1%) were MSI-H. There were 8 pathogenic mutations identified in 9 families (60%) in the Amsterdam positive group. 5 mutations were found in 5 families (26%) in the Bethesda positive group. 12 pathogenic mutations were identified, two of these are newly identified, and being published first in this work. These two new mutations were located on MLH1 (g.31276_35231del) and MSH2 (c.969_970delTC) genes. CONCLUSION: The prevalence of the mutations in the MLH1 and MSH2 genes was almost equal in our Hungarian colorectal cancer patients. One mutation in the MLH1 gene (c.143A > C; p.Q48P) was identified in three different families. Whether this mutation is the most frequent in the Hungarian population is still unidentified and warrant further investigation.

Difficulties in recognizing families with Hereditary Non-polyposis Colorectal Carcinoma. Presentation of 4 families with proven mutation.

INTRODUCTION: Hereditary Non-polyposis Colorectal Carcinoma is the most frequent genetic disease leading to colon and other malignancies. Recognizing the condition requires extensive family history going back several generations focusing particularly on the types of tumors occurring in the family at different age groups. METHODS: In families who met the Amsterdam and Bethesda Criteria, the removed tumor tissue was first examined by immunohistochemistry and microsatellite instability analysis. Subsequently DNA sequencing was performed to detect an underlying Mismatch Repair Gene mutation and multiple ligation dependent probe amplification was applied for recognizing large deletions in Mismatch Repair Genes. RESULTS: In the investigated families 3 pathogen mutations, 1 large deletion and 2 cases of polymorphism were found. There is considerable difference between the families in terms of the types of malignancies and the age in which those appeared. CONCLUSION: Recognizing families with Hereditary Non-polyposis Colorectal Carcinoma presents great difficulties because of the variety of phenotypes in presentation. Special attention should be paid to small families and those who present with cancer of other than colon origin. Practicing physicians should be made aware of the fact that this disease may have atypical presentations. Follow up of families who have already been screened may be difficult for social, economical or religious reasons.

Cell surface properties of L1210 leukaemia cells.

The surface properties of vincristine-colchicine sensitive and resistant L1210 leukaemic cells have been studied using concanavalin A mediated agglutination assay as well as electron microscopic visualization of concanavalin A receptors. 3H-colchicine uptake by the sensitive and resistant lines has also been compared. The resistant L1210 leukaemic cells proved less agglutinable than the sensitive ones at the same concanavalin A concentration. Previous treatments with either colchicine, vincristine or chlorpromazine caused a marked decrease in the agglutinability of the sensitive L1210 leukaemic cells, while agglutination of the resistant ones was lowered slightly by the same treatments. The 3H-colchicine uptake of the sensitive cells was three times higher than that of the resistant ones.