Efficacy and safety of sirolimus early conversion protocol in liver transplant patients with hepatocellular carcinoma: A single-arm, multicenter, prospective study.

Mammalian target of rapamycin (mTOR) inhibitor as an attractive drug target with promising antitumor effects has been widely investigated. High quality clinical trial has been conducted in liver transplant (LT) recipients in Western countries. However, the pertinent studies in Eastern world are paucity. Therefore, we designed a clinical trial to test whether sirolimus can improve recurrence-free survival (RFS) in hepatocellular carcinoma (HCC) patients beyond the Milan criteria after LT. This is an open-labeled, single-arm, prospective, multicenter, and real-world study aiming to evaluate the clinical outcomes of early switch to sirolimus-based regimens in HCC patients after LT. Patients with a histologically proven HCC and beyond the Milan criteria will be enrolled. The initial immunosuppressant regimens are center-specific for the first 4-6 weeks. The following regimens integrated sirolimus into the regimens as a combination therapy with reduced calcineurin inhibitors based on the condition of patients and centers. The study is planned for 4 years in total with a 2-year enrollment period and a 2-year follow-up. We predict that sirolimus conversion regimen will provide survival benefits for patients particular in the key indicator RFS as well as better quality of life. If the trial is conducted successfully, we will have a continued monitoring over a longer follow-up time to estimate indicator of overall survival. We hope that the outcome will provide better evidence for clinical decision-making and revising treatment guidelines based on Chinese population data. Trial register: Trial registered at http://www.chictr.org.cn: ChiCTR2100042869.

A DMSO-free hepatocyte maturation medium accelerates hepatic differentiation of HepaRG cells in vitro.

The most essential tools for studying drug hepatotoxicity, liver diseases, and bioartificial livers have always been models that can recapitulate liver physiology in vitro. The liver progenitor cell line HepaRG represents an effective surrogate of the primary hepatocyte. However, the differentiation of HepaRG relies on long-term induction using a high concentration of dimethyl sulfoxide (DMSO), which may compromise the research of drug metabolism and restrict the applicability of this hepatic model. Here, we present a novel hepatic maturation medium (HMM) for the differentiation of HepaRG, which is based on a cocktail of soluble molecules that mimick the in vivo environment. We showed that HMM could rapidly (about nine days) induce HepaRG differentiation into polarized hepatocytes with maturely metabolic functions. In addition, under three-dimensional culture conditions, the hepatic spheroids showed multiple liver functions and toxicity profiles close to those of primary human hepatocytes (PHH). Our work demonstrates the utility of HMM as an alternative to the DMSO-dependent differentiation protocol for HepaRG; moreover, these results facilitate the application of HepaRG.

Liver transplantation for biliary atresia: A single-center study from mainland China.

AIM: To summarize our single-center experience with liver transplantation (LT) for biliary atresia (BA). METHODS: From October 2006 to December 2012, 188 children with BA were analyzed retrospectively. The stage I group (from October 2006 to December 2010) comprised the first 74 patients, and the stage II group (from January 2011 to December 2012) comprised the remaining 114 patients. Finally, 123 liver transplants were performed in 122 (64.9%) patients, whereas 66 patients did not undergo LT due to denial by their parents or lack of suitable liver grafts. The selection of graft types depended on the patients' clinical status and whether a suitable living donor was available. The characteristics of patients in stages I and II were described, and the surgical outcomes of LT recipients were compared between the two stages. The Kaplan-Meier method was used to estimate the cumulative patient and graft survival rates, and the equality of survival distributions was evaluated using the log-rank test. RESULTS: The 188 children consisted of 102 boys and 86 girls. Their ages ranged from 3 to 144 mo with a median of 8 mo. One hundred and fifteen (61.2%) patients were born in rural areas. Comparing stage I and stage II patients, the proportion of patients referred by pediatricians (43.2% vs 71.1%, respectively; P < 0.001) and the proportion of patients who previously received a Kasai procedure (KP) (32.4% vs 44.7%, respectively; P = 0.092) obviously increased, and significantly more parents were willing to treat their children with LT (73% vs 86%, respectively; P = 0.027). Grafts from living donors (102/122, 83.6%) were the most commonly used graft type. Surgical complications (16/25, 64.0%) were the main reason for posttransplant mortality. Among the living donor liver transplantation recipients (n = 102), the incidence of surgical complications was significantly reduced (34.1% vs 15.5%, respectively; P = 0.029) and survival rates of patients and grafts were greatly improved (81.8% vs 89.7%, respectively, at 1 year; 75.0% vs 87.8%, respectively, at 3 years; P = 0.107) from stage I to stage II. CONCLUSION: The status of surgical treatments for BA has been changing in mainland China. Favorable midterm outcomes after LT were achieved as centers gained greater technical experience.

Preoperative hepatic hemodynamics in the prediction of early portal vein thrombosis after liver transplantation in pediatric patients with biliary atresia.

BACKGROUND: Portal vein thrombosis (PVT) is one of the main vascular complications after liver transplantation (LT), especially in pediatric patients with biliary atresia (BA). This study aimed to assess the preoperative hepatic hemodynamics in pediatric patients with BA using Doppler ultrasound and determine whether ultrasonographic parameters may predict early PVT after LT. METHODS: One hundred and twenty-eight pediatric patients with BA younger than 3 years of age underwent Doppler ultrasound within seven days before LT, between October 2006 and June 2013. The preoperative hepatic hemodynamic parameters were then compared between patients with early PVT (within 1 month following LT) and those without PVT. Receiver operating characteristic analysis was performed to determine the optimal cutoff value for predicting early PVT. RESULTS: Of the 128 transplant recipients, 41 (32.03%) had a hypoplastic portal vein (PV), 52 (40.63%) had hepatofugal PV flow and 40 (31.25%) had a high hepatic artery resistance index (HARI) of ≥1. Nine cases (7.03%) experienced early PVT. A PV diameter ≤4 mm (sensitivity 88.89%, specificity 72.27%), and a hepatofugal PV flow (sensitivity 77.78%, specificity 62.18%) with a high HARI ≥1 (sensitivity 77.78%, specificity 72.27%) were hepatic hemodynamic risk factors for early PVT. CONCLUSIONS: Hepatic hemodynamic disturbances in pediatric recipients with BA were more common. Small PV diameter (≤4 mm) and hepatofugal PV flow combined with high HARI (≥1) are strong warning signs of early PVT after LT in pediatric patients with BA. Intense monitoring of vascular patency and prophylactic thrombolytic therapy should be considered in pediatric patients undergoing LT for BA.

Bile duct kinking after adult living donor liver transplantation: Case reports and literature review.

Regeneration of the partial allograft and the growth of children may cause kinking of the biliary tract after pediatric living donor liver transplantation (LDLT), but bile duct kinking after adult LDLT is rarely reported. We herein presented two patients who suffered from anastomotic strictures caused by severe bile duct kinking after LDLT. The first patient was a 57-year-old woman with hepatitis B virus (HBV)-related liver cirrhosis, who developed biliary stricture 5 months after receiving right-lobe LDLT. Subsequently, endoscopic and percutaneous treatments were attempted, but both failed to solve the problem. The second was a 44-year-old woman also having HBV-related liver cirrhosis. Biliary stricture occurred 14 months after LDLT. Likewise, the guide wire failed to pass through the stricture when endoscopic interventions were conducted. Afterwards, both of the two cases underwent reexploration, showing that compensatory hypertrophy of the allografts resulted in kinking and sharp angulation of the bile ducts, and the anastomotic sites were found to be severely stenotic. Finally, re-anastomosis by Roux-en-Y procedure was successfully performed, and long-term stenosis-free survival was achieved in both of them. Our experience suggests that bile duct kinking after LDLT may play a role in the high incidence of anastomotic strictures in adult LDLT recipients, which may also result in the treatment failure of the non-surgical techniques for anastomotic strictures. Re-anastomosis in the form of Roux-en-Y hepaticojejunostomy is an effective surgical option for the treatment of such a condition.

Submassive hepatic necrosis distinguishes HBV-associated acute on chronic liver failure from cirrhotic patients with acute decompensation.

BACKGROUND & AIMS: Distinguishing between acute on chronic liver failure (ACLF) and decompensated liver cirrhosis is difficult due to a lack of pathological evidence. METHODS: A prospective single-center study investigated 174 patients undergoing liver transplantation due to acute decompensation of hepatitis B virus (HBV)-associated liver cirrhosis. Two groups were distinguished by the presence or absence of submassive hepatic necrosis (SMHN, defined as necrosis of 15-90% of the entire liver on explant). Core clinical features of ACLF were compared between these groups. Disease severity scoring systems were applied to describe liver function and organ failure. Serum cytokine profile assays, gene expression microarrays and immunohistochemical analyzes were used to study systemic and local inflammatory responses. RESULTS: SMHN was identified in 69 of 174 patients proven to have cirrhosis by histological means. Characteristic features of SMHN were extensive necrosis along terminal hepatic veins and spanning multiple adjacent cirrhotic nodules accompanied by various degrees of liver progenitor cell-derived regeneration, cholestasis, and ductular bilirubinostasis. Patients with SMHN presented with more severely impaired hepatic function, a higher prevalence of multiple organ failure (as indicated by higher CLIF-SOFA and SOFA scores) and a shorter interval between acute decompensation and liver transplantation than those without SMHN (p<0.01 for all parameters). Further analyzes based on serum cytokine profile assays, gene expression microarrays and immunohistochemical analyzes revealed higher levels of anti-inflammatory cytokines in patients with SMHN. CONCLUSIONS: SMHN is a critical histological feature of HBV-associated ACLF. Identification of a characteristic pathological feature strongly supports that ACLF is a separate entity in end-stage liver disease.

Living-donor or deceased-donor liver transplantation for hepatic carcinoma: a case-matched comparison.

AIM: To compare the surgical outcomes between living-donor and deceased-donor liver transplantation in patients with hepatic carcinoma. METHODS: From January 2007 to December 2010, 257 patients with pathologically confirmed hepatic carcinoma met the eligibility criteria of the study. Forty patients who underwent living-donor liver transplantation (LDLT) constituted the LDLT group, and deceased-donor liver transplantation (DDLT) was performed in 217 patients. Patients in the LDLT group were randomly matched (1:2) to patients who underwent DDLT using a multivariate case-matched method, so 40 patients in the LDLT group and 80 patients in the DDLT group were enrolled into the study. We compared the two groups in terms of clinicopathological characteristics, postoperative complications, long-term cumulative survival and relapse-free survival outcomes. The modified Clavien-Dindo classification system of surgical complications was used to evaluate the severity of perioperative complications. Furthermore, we determined the difference in the overall biliary complication rates in the perioperative and follow-up periods between the LDLT and DDLT groups. RESULTS: The clinicopathological characteristics of the enrolled patients were comparable between the two groups. The duration of operation was significantly longer (553 min vs 445 min, P < 0.001) in the LDLT group than in the DDLT group. Estimated blood loss (1188 mL vs 1035 mL, P = 0.055) and the proportion of patients with intraoperative transfusion (60.0% vs 43.8%, P = 0.093) were slightly but not significantly greater in the LDLT group. In contrast to DDLT, LDLT was associated with a lower rate of perioperative grade II complications (45.0% vs 65.0%, P = 0.036) but a higher risk of overall biliary complications (27.5% vs 7.5%, P = 0.003). Nonetheless, 21 patients (52.5%) in the LDLT group and 46 patients (57.5%) in the DDLT group experienced perioperative complications, and overall perioperative complication rates were similar between the two groups (P = 0.603). No significant difference was observed in 5-year overall survival (74.1% vs 66.6%, P = 0.372) or relapse-free survival (72.9% vs 70.9%, P = 0.749) between the LDLT and DDLT groups. CONCLUSION: Although biliary complications were more common in the LDLT group, this group did not show any inferiority in long-term overall survival or relapse-free survival compared with DDLT.

Liver transplantation for hepatocellular carcinoma exceeding the Milan criteria: a single-center experience.

PURPOSE: To establish a prognostic prediction system for patients with hepatocellular carcinoma (HCC) exceeding Milan criteria after liver transplantation (LT). METHODS: A total of 130 patients undergoing LT for HCC exceeding Milan criteria were enrolled into the study. Independent predictors for relapse-free survival (RFS) were adopted to establish a grading system to predict the risk of post-LT tumor recurrence. RESULTS: Multivariate Cox analysis revealed that tumor size >10 cm [vs. ≤ 5 cm: relative risk (RR) = 4.214, P < 0.001], preoperative alpha fetoprotein > 400 ng/ml (vs. ≤ 400 ng/ml: RR = 1.657, P < 0.001), extrahepatic invasion (RR = 2.407, P = 0.005) and vascular invasion (RR = 1.917, P = 0.013) were independent predictors for RFS. The risk index of each patient was defined as the sum of the RR obtained in the Cox analysis for RFS. The risk of tumor recurrence was classified into four grades: grade I-risk index equal to 0, grade II-risk index from 0 to 2, grade III-risk index from 2 to 6 and grade IV-risk index >6. RFS rates of patients with grade I-IV (n = 35, 46, 30 and 19) were 87.5, 57.8, 34.7 and 0 % in 1 year; and 74.4, 41.7, 14.4 and 0 % in 5 years. Both of overall survival (OS) and RFS correlated well with the risk index grade. Patients with grade I achieved comparable prognostic outcomes with the Milan group patients (n = 119) (5-year OS = 73.7 vs. 74.7 %, P = 0.748; 5-year RFS = 74.4 vs. 85.7 %, P = 0.148). CONCLUSIONS: The new grading system was proved to be a promising system in predicting the patient prognosis after LT for HCC exceeding Milan criteria.

Comparison of survival and tumor recurrence rates in patients undergoing liver transplantation for hepatitis B-related hepatocellular carcinoma using Milan, Shanghai Fudan and Hangzhou criteria.

OBJECTIVES: To assess the performance of the Milan, Shanghai Fudan and Hangzhou criteria based on a preoperative evaluation in patients undergoing liver transplantation (LT) for hepatitis B-related hepatocellular carcinoma (HCC). METHODS: Using a prospectively collected database, the data of consecutive patients with hepatitis B-related HCC undergoing LT at the Department of Liver Surgery of Ren Ji Hospital, School of Medicine, Shanghai Jiaotong University from January 2005 to December 2009 were reviewed. Overall survival and tumor recurrence rates of patients fulfilling the Milan, Shanghai Fudan and Hangzhou criteria were compared using log-rank test. RESULTS: Altogether 148 patients were enrolled in the study, among whom 88 fulfilled the Milan criteria and 24 and 39 were beyond Milan but within the Shanghai Fudan or Hangzhou criteria, respectively. After a median follow-up of 44 months, survival rates did not differ among the three groups (P = 0.8780). Recurrence rates were significantly higher for newly eligible patients by the Shanghai Fudan or Hangzhou criteria compared with those within the Milan criteria. CONCLUSIONS: The Milan criteria should be used as the preferred criteria for the selection of hepatitis B-related HCC for LT. Considering the high tumor recurrence rates and donor scarcity, a moderate expansion of the Milan criteria must be performed cautiously until high-quality clinical trials are conducted.

HIF1 regulates WSB-1 expression to promote hypoxia-induced chemoresistance in hepatocellular carcinoma cells.

WSB-1 is involved in DNA damage response by targeting homeodomain-interacting protein kinase 2 (HIPK2) for ubiquitination and degradation. Here, we report that hypoxia significantly up-regulates the expression of WSB-1 in human hepatocellular carcinoma (HCC) cells. We also provide evidence that WSB-1 is a target of hypoxia-inducible factor 1 (HIF-1). Silencing the expression of HIF-1α in HCC cells by RNA interference abolishes hypoxia-induced WSB-1 expression. Using chromatin immunoprecipitation and luciferase reporter assays, we identified a HRE of the WSB-1 gene. Moreover, silencing the expression of WSB-1 by RNA interference rescues HIPK2 expression in hypoxic HCC cells and promotes etoposide-induced cell death in hypoxic HCC cells. Taken together, these data shed light on the mechanisms underlying hypoxia-induced chemoresistance in HCC cells.

Living donor liver transplantation in 43 children with biliary atresia: a single-center experience from the mainland of China.

BACKGROUND: There is no large-cohort report on living donor liver transplantation (LDLT) for biliary atresia (BA) patients from the mainland of China. This single-center study describes our initial experience with 43 LDLTs for BA patients aged two years or younger. METHODS: In this study, the eligibility criteria were BA as the primary diagnosis and two years of age or younger. From October 2006 to December 2010, the clinical data of 43 LDLTs, including pre-operative evaluations, surgical techniques, postoperative complications and outcomes of donors and recipients, were retrospectively analyzed. RESULTS: Donor graft type was the left lateral segment with compatible ABO blood groups. Forty-three recipients were selected in this study. The median patient age at operation was 9 months (range 6-24), and the median body weight was 8 kg (range 5.7-12.5). Fourteen (32.6%) recipients received Kasai operations before liver transplantation. The overall one- and two-year cumulative survival rates for grafts and recipients were 81%, 81% and 76%, 76%, respectively. No donor mortality was encountered, with a minimal morbidity and no long-term sequelae. Nine out of 43 recipients died. Postoperative complications of recipients were biliary leakage and refluxing cholangitis (11/43, 25.6%), hepatic artery thrombosis (4, 9.3%), pulmonary infections (4, 9.3%), portal vein thrombosis (3, 7.0%), wound disruption (3, 7.0%), acute rejection (3, 7.0%), cytomegalovirus infection (2, 4.7%), and intra-abdominal bleeding (1, 2.3%). CONCLUSION: Despite the relatively low survival rates due to lack of experience initially, LDLT still provides encouraging outcomes for pediatric recipients with BA, even small children under two years old.

Invasive fungal infection after liver transplantation: risk factors and significance of immune cell function monitoring.

OBJECTIVE: Monitoring immune status in transplant recipients is essential for predicting the risk of infections. The aims of the study were to identify the correlation of a low ImmuKnow adenosine triphosphate (ATP) value with the development of invasive fungal infections (IFIs) and whether this is an independent risk factor for IFIs in liver recipients. METHODS: We followed up 248 liver recipients who developed 157 infectious episodes. Peripheral CD4(+) T cells were selected freshly for ATP detection. Percentages of T-helper (Th, CD3(+) CD4(+) ) and T-suppressor (Ts, CD3(+) CD8(+) ) lymphocyte subgroups were also examined. RESULTS: Overall 44 patients (17.7%) were diagnosed as IFIs, of whom 9 (20.5%) died. The average ImmuKnow ATP value in the IFI patients (109 ± 78 ng/mL) was significantly lower than that in common bacterial infections (174 ± 106 ng/mL, P < 0.01) or stable liver recipients (314 ± 132 ng/mL, P < 0.01), while there was no difference in the Th/Ts ratio among each group. Logistic regression analysis showed ImmuKnow ATP value less than 100 ng/mL was an independent risk factor of IFI (OR = 3.44, P = 0.0237). ImmuKnow ATP values had no correlation with lymphocytes or their subgroups, but tended to correlate with the number of neutrophils and total white blood cells. CONCLUSIONS: ImmuKnow assay monitoring has the potential to identify the patients at risk of developing IFI after liver transplantation (LT), which may provide a feasible measure for optimizing liver recipients' immune cellular function after transplantation.

Computed tomography perfusion in living donor liver transplantation: an initial study of normal hemodynamic changes in liver grafts.

Hepatic hemodynamic changes in grafts after living donor liver transplantation (LDLT) are complicated. In this study, computed tomography (CT) perfusion parameter values, especially portal vein perfusion (PVP), was retrospectively analyzed in recipients both with and without small-for-size syndrome (SFSS). PVP was significantly higher in non-SFSS recipients on post-operative day (POD) 14 or 28 than in normal donors before donation (p < 0.001 and p = 0.008, respectively), but it significantly decreased between 14 and 28 days post-operatively (p = 0.007). There was a significant inverse correlation between graft-to-recipient spleen size ratio and PVP on POD 14 in non-SFSS group (r = -0.545, p = 0.002). Furthermore, PVP in the SFSS group was significantly greater than in the non-SFSS group on POD 14 (p = 0.042). In conclusion, we successfully evaluated normal hemodynamic changes in grafts without SFSS by CT perfusion examination. To our knowledge, this is the first study on hemodynamic changes of living donor liver grafts using CT technique.

[Clinical study of diabetic retinopathy treated by compound danshen dripping pills].

OBJECTIVE: To observe the therapeutic effect of compound danshen dripping pills in visual function recovery of diabetic retinopathy. METHODS: 42 patients(78 eyes) with diabetic retinopathy of I-III phase were divided into two groups in random. 43 eyes were treated with compound danshen dripping pills and the other 35 eyes with vitamin BI and Luding C for three months. The visual acuity, fundus, visual field, fundus fluorescein angiography and visual electro-physiology were observed. RESULTS: The visual acuity in treated group were significantly improved after treatment and had significant difference with those in control group (P < 0.05). The number of micro-hemorrage, microaneurysm and the mean defect (MD) of visual field in treated group decreased obviously after treatment and had significant difference with that in control group (P < 0.05). The latent period of P100 wave and a, b wave in treated group were shorter than control group, and the wave amplitude were higher than that in control group. CONCLUSION: The compound danshen dripping pills can improve the visual acuity, control the micro-hemorrage and microaneurysm of fundus and have the effect in visual function recovery of diabetic retinopathy.

[Prospective study of liver parenchyma volume in hepatectomy of primary liver cancer].

OBJECTIVE: To explore the secure resection margin (RM) of hepatectomy for primary liver cancer (PLC) with the coexistence of cirrhosis or hepatitis by studying the correlations of the resected liver parenchyma volume with postoperative liver function, complication and RM clinically. METHODS: The volume of tumor and the surrounding liver in resected liver specimen was measured and calculated in continuous 76 PLC patients prospectively, and the total liver parenchyma volume was measured and calculated using computed tomography (CT) images in former 40 patients. Under ideal circumstances, the surrounding liver volume, which would be resected theoretically, was calculated according to various sizes of tumors and RMs. The correlations of the resected liver volume or hepatic parenchyma-resected rate (HPRR) with postoperative liver function, complication and RM were analysed. RESULTS: The RM was (5 +/- 7) mm in 76 patients. The volume of the tumors and the surrounding liver in the specimens were (107 +/- 203) cm(3) and (153 +/- 120) cm(3), respectively. In 40 patients, the total nontumorous liver volume using CT images was (1079 +/- 179) cm(3), and HPRR was (14 +/- 9)%. There were statistically significant differences in HPRR (P < 0.05) between three groups with complication score 0, 1-2 and 3-6 points, the value of the first group were lower than that of the third group at the level P < 0.05. The significant factors affecting liver function and complication are HPRR, the size of operation, the time of hepatic portal occlusion and the resected liver volume (P < 0.05) apart from preoperative liver function. CONCLUSIONS: When hepatectomy was performed in PLC patients with preoperative liver function of Child A grade and the coexistence of cirrhosis or hepatitis, 30% HPRR was a lower limit for greatly increasing the chance of developing serious postoperative complications, while 20% HPRR was a safe upper limit for achieves quick postoperative recovery or developing only a few mild complications. When PLC patients without macroscopic tumor thrombi or macrosatellites undergo hepatectomy, 10 mm RM is enough to ensure sufficient liver function residue and achieve complete micrometastasis clearance in liver parenchyma surrounding the lesion if the diameter of a tumor is less than 10 cm and 6 mm RM is enough to ensure sufficient liver function residue and obtain 99% micrometastasis clearance if the diameter of a tumor is greater than 10 cm, while with macroscopic tumor thrombi or macrosatellites, 20 mm RM is enough to ensure sufficient liver function residue and achieve 99% micrometastasis clearance if the diameter of a tumor is less than 6 cm.

Combined hepatic resection with fenestration for highly symptomatic polycystic liver disease: A report on seven patients.

AIM: To evaluate the immediate and long-term results in a series of patients with highly symptomatic polycystic liver disease (PLD) treated by combined hepatic resection with cystic fenestration. METHODS: We reviewed our recent experience with a combined hepatic resection-fenestration procedure in seven highly symptomatic patients with PLD. Clinical data, liver manifestation of computed tomography (CT), and morbidity were recorded pre- and post-operation. Follow-up was made by clinical and CT examinations in all patients. RESULTS: Symptomatic relief and reduction in abdominal girth were obtained in all patients during an average follow-up period of 20.4 mo. CT scans confirmed post-resection hypertrophy of the spared liver and lack of significant cyst progression. All patients had mild to severe ascites. Two patients were complicated with pleural effusion. CONCLUSION: Some highly symptomatic patients with massive PLD may benefit from combined hepatic resection and fenestration at acceptable risk. To stitch the dissected hepatic ligaments could prevent the instable remnant liver from kinking and collapsing.

Disseminated tumor cells homing into rats' liver: a new possible mechanism of HCC recurrence.

AIM: To detect the origin of hepatocellular carcinoma (HCC) recurring and attempt to propose a new recurrent mechanism. METHODS: Orthotopic liver allotransplantation was performed on male rats with HCC- induced by diethylnitrosamine using female donors. Metastatic tumors in transplanted livers were obtained. A DNA probe that exhibits specificity for the rat Y chromosome was generated by using a set of primers specific to murine sry gene. In situ hybridization (ISH) for Y chromosome was used to detected the origin of HCC recurring. Male HCC tissue was designed to be positive control. ISH on female tissue and using non-labeled with DIG probe was thought to be negative control. RESULTS: Positive marks were seen through ISH for Y chromosome in recurrent tumor tissue and positive control. No signal was detected in both negative controls. CONCLUSION: Recurrent HCC after liver transplantation originated from disseminated tumor cells in recipients. Extrahepatic cells homing into liver may be a new HCC recurrence mechanism. Likewise, it implicates that this mechanism is responsible for HCC recurring after hepatectomy.