Síndrome metabólico, hígado graso no alcohólico y hepatocarcinoma / Metabolic syndrome, nonalcoholic fatty liver disease and hepatocellular carcinoma

En las últimas décadas, los cambios en el estilo de vida pro-vocaron un incremento en la prevalencia del síndrome meta-bólico y que la enfermedad por hígado graso no alcohólico (nonalcoholic fatty liver disease, NAFLD sus siglas en inglés) se convierta en la enfermedad hepática crónica más fre-cuente en todo el mundo. Los componentes del síndrome metabólico no son sólo altamente prevalentes en pacientes con hígado graso no alcohólico, sino que a la vez aumentan el riesgo de desarrollarlo. Esta relación bidireccional ha sido claramente establecida. Asimismo se considera que NAFLD podría ser el componente hepático del síndrome metabólico. Aunque NAFLD se considera principalmente una enfermedad benigna, puede progresar a fibrosis hepática grave y carcino-ma hepatocelular (CHC), incluso se encontraría este último en hígados no cirróticos. El objetivo de esta revisión es determinar los procesos fisio-patológicos comunes a estas entidades, cuáles son las estra-tegias diagnósticas recomendadas y cuáles las intervenciones terapéuticas actualmente aprobadas.

Estudo genômico do tumor embrionário hepatoblastoma / Genomic study of the embryonal tumor hepatoblastoma

O hepatoblastoma, câncer de fígado mais comum na infância, é um tumor embrionário que se supõe surgir da interrupção da diferenciação hepática durante a embriogênese. O genoma deste tipo tumoral carrega poucas alterações somáticas, principalmente aneuploidias cromossômicas e mutações em CTNNB1. Essa relativa escassez de mutações somáticas representa um desafio à estratificação de risco dos pacientes e ao desenvolvimento de terapias direcionadas. Neste trabalho, investigamos por sequenciamento de exoma o espectro de mutações somáticas em um grupo de 10 hepatoblastomas, pareados com suas respectivas amostras germinativas, incluindo um caso de tumor congênito. Os dados genômicos revelaram que os hepatoblastomas tem número reduzido de mutações somáticas codificadoras não-sinônimas (média de ~6 variantes/tumor, com exclusão do caso congênito), totalizando 94 mutações (92 diferentes) nos 10 tumores, mapeadas em 87 genes. Apenas três genes apresentaram mutações detectadas em mais de uma amostra, CTNNB1, CX3CL1 e CEP164. As mutações foram validadas pelo sequenciamento de um painel composto pelos genes identificados no exoma, também utilizado para investigar estes genes em um grupo adicional de 12 tumores; apenas mutações em CTNNB1 foram detectadas neste grupo adicional. Mutações somáticas em CTNNB1 foram detectadas em ~54% do grupo estudado (22 hepatoblastomas): sete variantes patogênicas do tipo nucleotídeo único (SNV) ou indel foram identificadas em oito hepatoblastomas (~36%), uma delas nunca previamente descrita (A21_S33del); deleções intragênicas foram detectadas por sequenciamento Sanger em quatro outros tumores (~18%). A proteína ß-catenina foi avaliada por imunohistoquímica, apresentando translocação para o núcleo, o que indica ativação da via WNT; esse resultado também foi observado em tumores nos quais mutações em CTNNB1 não foram detectadas. O principal achado do estudo do exoma de hepatoblastomas foi a identificação de uma mutação somática recorrente no éxon 3 do gene CX3CL1 (A235G), observada em dois diferentes tumores. A análise de expressão gênica e proteica de CX3CL1 e de seu receptor CX3CR1 revelou aumento de expressão de CX3CL1 em hepatoblastomas; este resultado foi replicado em duas coortes independentes. O detalhamento da análise evidenciou um padrão bimodal: (a) linfócitos infiltrados em regiões tumorais de inflamação pós-quimioterapia eram negativos para essas proteínas, que deveriam estar expressas neste tipo celular em condições normais, enquanto as células tumorais as expressavam; (b) nas áreas de necrose tumoral pós-quimioterapia, houve detecção das proteínas CX3CL1/CX3CR1 nos linfócitos, mas não nas células tumorais. Em conjunto, estes resultados sugerem que a ativação da via CX3CL1/CX3CR1 ocorre em parte dos hepatoblastomas, independentemente da detecção de mutações, o que parece ser um achado relevante, potencialmente relacionado a inflamação e/ou resistência à quimioterapia. Adicionalmente, três assinaturas mutacionais foram detectadas nos hepatoblastomas, duas delas com predomínio das assinaturas do COSMIC, HB-S1 (COSMIC 1 e 6, presentes em todos os tipos de câncer) e HB-S2, com similaridades à assinatura COSMIC 29, relacionada apenas a carcinoma oral de células escamosas (gengivo-bucal) associado ao hábito de mascar tabaco; uma nova assinatura mutacional foi observada em um subconjunto de hepatoblastomas (HB-S3), com padrão inespecífico de pequeno aumento de mutações C>A. As assinaturas mutacionais já relatadas para câncer de fígado não foram evidentes nestes hepatoblastomas, sugerindo um processo mutacional diferente em sua origem. Por fim, análise de mutações germinativas no caso de hepatoblastoma congênito levou à identificação de variantes germinativas em genes de predisposição a câncer (BRCA1 e FAH), levantando a questão do papel da predisposição genética no desenvolvimento destes tumores embrionários (AU)

Hepatoblastoma, the most common liver cancer in infancy, is an embryonal tumor supposed to arise from differentiation impairment during embryogenesis. Hepatoblastomas genomes carry few somatic changes, mainly chromosomal aneuploidies and mutations in the CTNNB1 gene. This relative paucity of somatic mutations poses a challenge to risk stratification and development of targeted therapies. In this work, we investigated the burden of somatic mutations in a cohort of 10 hepatoblastomas paired with their respective germline samples, including a case of congenital tumor. Data revealed a low number of non-synonymous somatic coding mutations (mean of ~6 variants/tumor), totalizing 94 mutations in the 10 tumors, mapped in 87 genes; only three genes exhibited mutations detected in more than one sample, CTNNB1, CX3CL1 and CEP164. Target sequencing was used for validation and screening of the mutated genes in an additional group of 12 tumors; only CTNNB1 mutations were detected in this additional group. CTNNB1 mutations were detected in ~54% of the cohort (22 hepatoblastomas): seven single nucleotide variant or indel mutations were identified in eight hepatoblastomas (~36%), including the A21_S33del mutation, not previously reported; intragenic deletions were detected by Sanger sequencing in 4 tumors (~18%). The ß-catenin protein was evaluated by immunohistochemistry, presenting translocation to the nucleus, indicating activation of the WNT pathway; this result was also observed in tumors without CTNNB1 mutations. The main finding of the exome study was the identification of a recurrent somatic mutation in the exon 3 of the CX3CL1 gene (A235G) in two different hepatoblastomas. Gene expression and protein analysis of CX3CL1 and its receptor CX3CR1 revealed increased expression of CX3CL1 in hepatoblastomas, a result that was replicated in two independent cohorts. A bimodal pattern of expression was observed: (a) lymphocytes infiltrated in tumor regions of inflammation post-chemotherapy were negative for these proteins, which should be expressed in this cell type under normal conditions, while the tumor cells expressed them; (b) in areas of tumor necrosis after chemotherapy, CX3CL1/CX3CR1 proteins were detected in lymphocytes, but not in tumor cells. Taken together, these results suggest that activation of the CX3CL1/CX3CR1 pathway occurs in part of the hepatoblastomas, regardless of mutation detection, potentially related to inflammation and/or resistance to chemotherapy. Additionally, three mutational signatures were detected, two of them with a predominance of signatures of COSMIC, HB-S1 (COSMIC 1 and 6, present in all types of cancer) and HB-S2 (COSMIC 29 signature, related only to oral cell carcinoma gingival-buccal associated with the habit of chewing tobacco). A new mutational signature was observed in a subset of hepatoblastomas (HB-S3), with a non-specific pattern of small increase in C>A mutations. Mutational signatures already reported for liver cancer were not evident in these hepatoblastomas, suggesting a different mutational process. Finally, an exploration of germline mutations in the congenital hepatoblastoma led to the identification of variants in genes of cancer predisposition (BRCA1 and FAH), raising the question of the role of genetic predisposition in the development of these embryonal tumors (AU)

The Correlation between NK Cell and Liver Function in Patients with Primary Hepatocellular Carcinoma

BACKGROUND/AIMS: This study aimed to detect the expression of natural killer (NK) cell receptor natural killer group 2D (NKG2D) in the peripheral blood of patients with primary hepatocellular carcinoma and to discuss the correlation between NK cell cytotoxicity and liver function. METHODS: The number of NK cells and the expression of NK cell receptor NKG2D in peripheral blood were determined by flow cytometry in patients with primary hepatocellular carcinoma, hepatitis B cirrhosis, chronic hepatitis B, and healthy controls. RESULTS: When compared with patients in the healthy and the chronic hepatitis B groups, the primary hepatocellular carcinoma group showed significant decreases in all parameters, including the cytotoxicity of NK cells on K562 cells, expression rate of NKG2D in NK cells, number of NKG2D+ NK cells, expression level of NKG2D, and number of NK cells (p<0.05). The activity of NK cells showed a positive correlation, whereas the Child-Pugh scores in the primary hepatocellular carcinoma and the hepatitis B cirrhosis groups showed a negative correlation with all parameters detected above. CONCLUSIONS: The decrease of NK cell activity in patients with primary hepatocellular carcinoma is closely related to their lower expression of NKG2D. Liver function affects the expression of NKG2D and the activity of NK cells.

The hypothesis of an effective strategy for resistance of hepatocellular carcinoma to therapy-autophagy / La hipótesis de una estrategia efectiva para la resistencia del carcinoma hepatocelular a la terapia autofágica

Hepatocellular carcinoma (HCC) is one of the most common malignant tumours and its five-year survival rate remains low. Autophagy is a catabolic process conserved among all eukaryotes ranging from yeast to mammals. Recently, many studies show that tumour cells can utilize autophagy as a cellular defence mechanism when facing metabolic stress. Thus, we hypothesize that autophagy may play an important role in the resistance of hepatocellular carcinomas to therapy. Although the exact role of autophagy on tumour cells is still complex and further studies are needed to prove the impact of autophagy on HCC, it suggests that autophagy may be a new therapeutic target for the resistance to therapy of HCC.

El carcinoma hepatocelular (CHC) es uno de los tumores malignos más comunes, y su tasa de super-vivencia a los cinco años sigue siendo baja. La autofagia es un proceso catabólico conservado en todos los eucariotas, que abarca desde las levaduras hasta los mamíferos. Recientemente, numerosos estudios han demostrado que las células tumorales pueden utilizar la autofagia como un mecanismo celular de defensa frente al estrés metabólico. De este modo, sostenemos la hipótesis de que la autofagia puede desempeñar un papel importante en la resistencia de los carcinomas hepatocelulares a la terapia. Aunque el papel exacto de la autofagia en las celulares tumorales sigue siendo complejo, y se requieren más estudios a fin de probar el impacto de la autofagia en el CHC, hay indicios de que la autofagia puede ser un nuevo objetivo terapéutico para la resistencia a la terapia del CHC.

Expression of decoy receptor 3 in liver tissue microarrays.

Background. Decoy receptor 3 (DcR3), a new member of the tumour necrosis factor receptor (TNFR) superfamily, is amplified and overexpressed in various cancers. We investigated the expression of DcR3 protein in liver tissue microarrays and assessed its importance in patients with hepatocellular carcinoma (HCC). Methods. In this retrospective study, tissue from 120 patients with HCC, 48 with tissue at least 2 cm away from the tumour (juxta-tumour tissue), 62 with cirrhosis and 23 with normal livers were studied as tissue microarrays. Immunohistochemistry was used to detect the expression of DcR3. Statistical analyses were done to assess the association between DcR3 expression and the clinicopathological features of HCC. Results. The positivity rate of DcR3 in HCC tissue was significantly higher than that in juxta-tumour tissue, cirrhosis and normal liver (p=0.017, p<0.0001, p<0.0001, respectively). The positive rate of DcR3 in juxta-tumour and cirrhotic tissue both increased significantly when compared with normal liver tissue (p<0.0001, p=0.005, respectively). The positivity rate of DcR3 in HCC in clinical TNM stages I and II was significantly lower than that in stages III and IV (p<0.0001). The positivity rate of DcR3 in patients without metastasis within 20 months decreased significantly compared with those with metastasis (p<0.0001). DcR3 expression in patients with alphafoetoprotein levels >400 g/L, portal vein tumour emboli, capsular infiltration and multicentric tumour was significantly higher than in groups without these features (p=0.021, p<0.0001, p<0.0001, p=0.002, respectively). Conclusion. The overexpression of DcR3 might play an important role in the pathogenesis, progression and metastases of HCC. The DcR3 gene might serve as an important molecular biological indicator in diagnosing and predicting the biological behaviour of patients with HCC.

Transcatheter Arterial Chemoembolization of Hepatocellular Carcinoma: Prevalence and Causative Factors of Extrahepatic Collateral Arteries in 479 Patients

OBJECTIVE: We wanted to investigate the prevalence and causative factors of extrahepatic arterial blood supply to hepatocellular carcinoma (HCC) at its initial presentation and during chemoembolization. MATERIALS AND METHODS: Between February 1998 and April 2000, consecutive 479 patients with newly diagnosed HCC were prospectively enrolled into this study. A total of 1629 sessions of transcatheter arterial chemoembolization (TACE) were performed in these patients (range: 1-15 sessions; mean: 3.4 sessions) until April 2004. For each TACE procedure, we determined the potential extrahepatic collateral arteries (ExCAs) depending on the location of the tumor, and we performed selective angiography of all suspected collaterals that could supply the tumor. The prevalence of ExCAs and the causative factors were analyzed. RESULTS: At initial presentation, 82 (17%) of these 479 patients showed 108 ExCAs supplying tumors. Univariate analysis showed that tumor size (p or = 5 cm) was significantly higher than that for those patients with a small tumor (< 5 cm) (p < 0.01). CONCLUSION: The presence of ExCAs supplying HCC is rather common, and the tumor size is a significant causative factor for the development of these collateral arteries.

Polimorfismo genético da glutationa S-transferase u1 (GSTM1) nas lesões hepáticas secundárias à infecção pelo vírus da heptite C antes e após o transplante hepático: associação com o carcinoma hepatocelular / Genetic polymorphism of glutatione S-transferase u1 (GSTM1) in hepatic lesions secondary to hepatitis

Avaliou-se, em pacientes transplantados por cirrose pelo vírus da hepatite C, a associação entre o genótipo nulo do gene glutationa S- transferase M1 e: a) ocorrência do carcinoma hepatocelular e/ou nódulo displásico de alto grau no fígado explantado; b) ocorrência da recidiva e gravidade da hepatite C no enxerto. Este gene foi analisado por técnica de PCR através do DNA extraído de blocos de parafina do fígado explantado, respectiva vesícula biliar, biópsia do tempo zero do transplante hepático e da recidiva da hepatite C no enxerto quando a mesma ocorreu. O genótipo nulo deste gene foi associado com a ocorrência do carcinoma hepatocelular e/ou nódulo displásico de alto grau no explante / This study evaluated the association of null genotype of glutathione S-transferase M1 in patients submitted to a liver transplant for cirrhosis due to hepatitis C virus infection and: a) the ocurrence of hepatocellular carcinoma and/or high grade dysplastic nodule in explanted liver; b) recurrence of hepatitis C and it’s severity in the graft. This polymorphism was evaluated by PCR of DNA extracted from paraffin blocks of explanted liver and gallblader, biopsies of time zero of liver transplantation and recurrence of hepatitis C when it happened. This polymorphism was associated with the ocurrence of hepatocellular carcinoma...

O valor da ressonância magnética na detecção de nódulos hepáticos utilizando-se diversas técnicas ponderadas em T2: existe consenso? / The value of magnetic resonance imaging for the detection of focal liver lesions using different T-2 weighted techniques: is there a consensus?

Desde o início da década de 80 a ressonância magnética vem sendo utilizada para o estudo do abdome e principalmente na detecção de nódulos hepáticos. As imagens ponderadas em T2 são as que trouxeram maior benefício quando comparadas à tomografia computadorizada com contraste. Inúmeras técnicas e seqüências de ressonância magnética ponderadas em T2 surgiram desde então, na tentativa de aumentar a eficácia diagnóstica, com menores tempos de exame. Neste sentido, foram publicados inúmeros trabalhos demonstrando a utilidade de seqüências rápidas e ultra-rápidas, com e sem supressão de gordura, em apnéia, com sincronizador respiratório e com bobinas de sinergia, entre outros avanços tecnológicos. No entanto, não há um consenso sobre qual a técnica mais apropriada e sensível para a detecção de lesões hepáticas focais. Neste artigo fazemos uma revisão bibliográfica e análise crítica das diversas técnicas de imagens ponderadas em T2, no que diz respeito às suas sensibilidades na detecção de nódulos hepáticos

Since the early 1980's several magnetic resonance imaging pulse sequences have been developed in order to determine the optimum imaging technique for the detection and characterization of hepatic lesions. T2-weighted images play an important role in the evaluation of the liver and present equal or greater sensitivity than enhanced computed tomography for the detection of liver lesions. New techniques for obtaining T-2 weighted images have been developed in the attempt to optimize the method. These techniques have improved the image quality by shortening examination time, reducing motion artifacts, and improving contrast-to-noise ratio. The effectiveness of the different techniques (fat suppression, breath-hold, respiratory-triggered and phased-array coils) has been tested in many comparative studies, although the results are controversial. In this article we review the literature and discuss the several T2-weighted image techniques, particularly with regard to sensitivity to detect focal liver lesions.

Three-dimensional conformal radiation therapy and periodic irradiation with the deep insipration breath-hold technique for hepatocellular carcinoma.

Nine cases of primary hepatocellular carcinoma were treated with 3D-conformal radiation therapy using computerized planning system. This technique permits the precise delivery of a high dose of radiation to the target while sparing most of the normal liver tissue. In order to decrease the effect of organ movement related to respiration, periodical irradiation was combined with the deep inspiration breath-hold technique. The radiation dose was equivalent to conventional radiation with a total dose of 50-70 Gy with 2 Gy, 5 times a week. Irradiation was given in 1-10 fractions which encompassed the target with 90 per cent isodose line. The patients tolerated the treatment procedure well without any complications inherent to the technique. The tumors were decreased in size, the pain symptom and abdominal discomfort were relieved for 3-20 months. This technique is an effective and safe treatment for palliation in hepatocellular carcinoma especially in locally advanced stages with large or multiple lesions. However, long term follow-up should be done to evaluate the late radiation effect and clinical outcome.

Ruptura espontânea de hepatocarcinoma em fígado cirrótico: uma causa rara de hemoperitônio / Spontaneous rupture of hepatocarcinome in cirrotic liver: a rare case of hemoperitoneum

Os autores relatam o caso de um paciente do sexo masculino previamente hígido, que apresentou quadro agudo de deterioração clínica e queda do hematócrito. A paracentese abdominal confirmou hemoperitônio e a laparotomia post-mortem demonstrou massa hepática consistente com carcinoma hepatocelular. Alguns aspectos desta apresentação incomum são discutidos

Morphological study of hepatic megakaryocytopoiesis in New Zeland white rabbits during intrauterine and postnatal development

We studied hepatic megakaryocytopoiesis in New Zeland White rabbits during the intrauterine phase and after birth. Sixt females were sacrificed, two of them on the 15(th) day of pregnancy for embryo liver collection, and two on the 22(nd) and 29(th) day of pregnancy for fetus embryo collection. Six other females were allowed to complete gestation and liver of newborn rabbits was obtained on the 10(th), 21(st) and 32(nd) day after birth. Morphologically, the megakaryocytes presented scarce to abundant cytoplasm, with staining affinity ranging from slightly basophilic acidophilic. Masson trichrome staining revealed a large reddish and irregular nucleus (oval, reniform, karyokinetic and lobulated) with loose to dense chromatin and with a visible number of nucleoli depending on the chromatin pattern.

Correlation of changes in natural killer cell activity and glutathione S-transferase placental form positive hepatocytes in diethylnitrosamine-induced rat hepatocarcinogenesis

To evaluate the induction of preneoplastic hepatic foci in relation to natural killer cell (NK) activity, we sequentially analyzed glutathione S-transferase placental form positive (GST-P+) hepatocytes and NK activity during diethylnitrosamine (DEN) and phenobarbital (PB)-induced hepatocarcinogenesis in Sprague-Dawley rats. Previous studies have shown that NK activity can modulate the carcinogenic process induced by chemical carcinogens. Newborn females were initially given a single intraperitoneal injection of 15 mg DEN/kg and three weeks later, they were treated with 500 ppm phenobarbital (PB). From week 3, PB was administered in drinking water for 9 weeks. Interim and terminal sacrifices were performed at weeks 12, 15 and 30. GST-P+ hepatocytes increased with age in DEN-treated rats, especially in the population of more than two GST-P+ hepatocytes. The NK activity of DEN-treated rats did not significantly differ from that of control rats until week 12, but it progressively decreased from week 15 to 30. These results indicate that changes of NK activity inversely correlated with the induction of preneoplastic hepatic foci. This strong correlation of decreased NK activity with enhanced induction of GST-P+ foci suggests that NK activity is important in the early progression of hepatocarcinogenesis in rats.

Studies on DNA sequencing of K-ras-2 Gene in patients with liver and pancreas cancer

Point mutations in K-ras-2 gene were detected either in primary liver or pancreas cancer patients using polymerase chain reaction followed by polyacrylamide DNA sequencing determination analysis. The frequencies of point mutations which found liver tumors were mainly due to adenine base insertion, whereas in pancreatic tumors cytosine insertion type was found to be abundant. Both types of tumors showed guanine deletion of K-ras-2 mutations. This work shed light on the possibility of using point mutations in K-ras-2 gene as a useful approach for differential diagnosis of cancers

Carcinoma escamoso primario de hígado / Hepatic squamous carcinoma

Informamos un caso de carcinoma escamoso primario de hígado en un paciente masculino de 38 años de edad. Se realizó una revición de la literatura mundial encontrando únicamente 12 casos reportados y todos ellos en pacientes masculinos; no encontramos reportes de este tumor en la literatura mexicana. El pronóstico de estas lesiones es malo y la sobrevida promedio no es mayor de seis meses

Abnormalities of the interdigestive migrating motor complex in a patient with carcinoid syndrome

As pressöes intraluminais do antro gástrico, duodeno e jejuno foram registradas durante 206 minutos após jejum de 12 horas em uma paciente com síndrome carcinóide devida a neoplasia de células enterocromafins do ileo e com metástasis hepáticas. A alteraçäo mais conspícua foi a presença de taquirritmia de 16-17 ondas de pressäo/minuto, predominando nos "fronts" de atividade tanto no duodeno como no jejuno. Períodos com 11-12 ondas/minutos apareceram irregularmente e a ocorrência simultânea de 12 ondas/minuto no duodeno e 16 ondas/minuto no jenuno foi registrada. O antro gástrico permaneceu em quiescência motora durante todo o transcurso do estudo manométrico. Presume-se que as alteraçöes sejam produzidas pelas substâncias secretadas pelo tumor carcinóide

Combined use of tamoxifen, cyclosporin A, and verapamil for modulating multidrug resistance in human hepatocellular carcinoma cell lines

The intensive use of chemotherapeutic agents for the treatment of cancer has resulted in the cure or improved survival of many patients. But unfortunately, many cancers including human hepatocellular carcinoma (HCC) don't respond to chemotherapy. One of the major mechanisms for the drug resistance in the HCC is an elevated MDR1 RNA expression which makes cells become multidrug resistant. To overcome the multidrug resistance (MDR) phenotype, a high dose of verapamil is required both clinically and experimentally. Accordingly we have examined the MDR modulating effects with combinations of tamoxifen, cyclosporin A, and verapamil in vitro with the physiologically achievable concentrations of each agent, i.e., 2.0 microM/L for tamoxifen, 1.6 microM/L for cyclosporin A, and 2.5 microM/L for verapamil respectively in HCC lines. As expected, verapamil alone with the physiologically achievable concentration at which we tested didn't enhance the doxorubicin cytotoxicity in the HCC lines. Furthermore, any verapamil combination with cyclosporin A or tamoxifen was not effective in overcoming the doxorubicin resistance in the high MDR1 expressor (Hep-G2) line. However tamoxifen reduced the IC50 of doxorubicin by a factor of 1.9 in the low MDR1 expressor (SK-Hep1) and 1.1 in the high MDR1 expressor line (p< 10(-5) respectively). Of interest, combinations of tamoxifen and cyclosporin A showed a significant reduction in the IC50 of doxorubicin in both HCC lines. The IC50 of doxorubicin was reduced by a factor of 3.9 and 1.3, i.e., from 0.023943 micrograms/ml to 0.006157 micrograms/ml (p< 10(-5)) in the SK-Hep1 cell line, and 0.068819 micrograms/ml to 0.052442 micrograms/ml (p< 10(-5)) in Hep-G2 respectively when tamoxifen and cyclosporin A were administered together. Both the estrogen and progesterone receptors in the SK-Hep1 and Hep-G2 lines were less than 0.01 fmol/mg of cytosol protein, respectively. It is therefore suggested that the reversal of doxorubicin resistance is unrelated to their anti-estrogenic activity in the HCC lines. Three modulator combinations of tamoxifen, cyclosporin A, and verapamil were not more effective than the combination of tamoxifen and cyclosporin A on the sensitivity to doxorubicin. MDR modulators of tamoxifen, cyclosporin A, and verapamil didn't reduce the IC50 of cisplatin to the clinically achievable concentration range in HCC lines. In summary, the combination of tamoxifen and cyclosporin A at the concentrations normally seen after clinical administration of these modulators showed significant synergism on the sensitivity to doxorubicin in both low and high MDR1 expressor HCC lines. These data indicate the need for in vivo trials.