Primary hepatic carcinoid tumors confirmed with long-term follow-up after resection

Primary carcinoid tumor of the liver is very rare. Only 30 cases have been reported in the English literature. However, most of those cases were diagnosed only on the basis of diagnostic imaging and surgical exploration, their follow-up periods being up to 5 years. Considering the slow progression of the tumor, long-term follow-up is required to exclude occult extrahepatic primaries which may manifest afterwards, and to determine the clinical course of this disease. We experienced 3 patients with primary hepatic carcinoid tumors who underwent total resections. They all survived more than 7 years and were clinically confirmed as hepatic primary by failing to detect other primaries during their courses. One patient is disease-free for more than 7 years after resection. The other 2 were found to have recurrence in the remnant liver; 1 underwent transcatheter arterial embolization several times and is alive more than 4 years after recurrence, and the other underwent 2 more operations and survived 8 years after the 1st recurrence. Surgery might offer a possible chance of cure for primary hepatic carcinoid tumor, and transcatheter arterial embolization might be a good treatment option when an unresectable disease is confined to the liver.

Metachronous bile duct cancer in a patient surviving for a decade and undergoing curative surgery twice

We report a 75-year-old woman with metachronous bile duct cancer who underwent curative resection twice and has survived for a decade. In 1989, she was admitted because her serum alkaline phosphatase level was elevated. Computed tomography (CT) showed a low-density mass, 2 cm in diameter, at the left hepatic duct and intrahepatic bile duct dilatation in the left lobe. We diagnosed the lesion as an intrahepatic bile duct cancer and performed extended left hepatic lobectomy with systematic lymph node dissection. The histological diagnosis was a well differentiated cholangiocellular carcinoma with hepatic hilar and celiac lymph node metastases (T1N2M0, Stage IVB). In 1996, she was re-admitted with obstructive jaundice. CT showed a slightly enhanced mass, 4 cm in diameter, in the pancreatic head. After reducing the jaundice by percutaneous transhepatic biliary drainage, pancreatoduodenectomy was performed. The histological diagnosis of this lesion was a moderately differentiated adenocarcinoma originating from the intrapancreatic bile duct. Ten years after the first operation, she is leading a normal daily life with no cancer recurrence. These findings suggest that repeated curative surgery can result in a long-term survival of patients with metachronous bile duct cancer.

Versatility of the inferior epigastric artery as an interpositional vascular graft in living-related liver transplantation

We have used the recipient inferior epigastric artery as an interpositional vascular graft in living-related liver transplantation cases with hepatic artery obstruction, enabling us to restore the arterial inflow sufficiently to the transplanted liver. The inferior epigastric artery is easy to access during abdominal surgery. Easy to harvest, it is anatomically constant and has a caliber equivalent to that of the hepatic artery. Donor site morbidity is negligible. There is no risk of rejection because of the autograft. There has been no report on the availability of the inferior epigastric artery for hepatic artery reconstruction. We consider this vessel as a good option for an arterial conduit in case of the inadequacy or thrombosis of the hepatic artery in living-related liver transplantation.

Targeting endogenous platelet-derived growth factor B-chain by adenovirus-mediated gene transfer potently inhibits in vivo smooth muscle proliferation after arterial injury

Platelet-derived growth factor (PDGF), especially its B chain, has been implicated in the pathogenesis of vascular proliferative disorders such as atherosclerosis and restenosis after angioplasty. We constructed a replication-deficient recombinant adenovirus containing the gene encoding the extracellular region of PDGF beta-receptor (PDGFXR) that binds PDGF-B chain and acts as its antagonist. The administration into balloon-injured rat carotid arteries of an adenovirus containing the Escherichia coli lacZ gene as a marker gene at 5 days after injury markedly facilitated efficacy of gene transfer, as compared with its administration immediately after injury. Adenovirus-mediated gene transfer of PDGFXR into injured arteries performed at 5 days resulted in a more than 50% reduction in the neointimal area of injured arteries at 14 days. In contrast, the administration of control adenoviruses containing lacZ gene or containing no foreign gene was without suppressive effects on neointima formation. The inhibition of neointima formation by the expression of PDGFXR was accompanied by a reduction in bromodeoxyuridine-labeled cells and nearly complete inhibition of tyrosine phosphorylation of both alpha- and beta-receptors for PDGF, but not of epidermal growth factor receptor, in injured arteries. This is the first report to indicate the usefulness of targeting a growth factor by expressing an extracellular binding region of a receptor using an adenovirus for the treatment of vascular proliferative disorders, and provide direct evidence that PDGF-B chain plays an essential role in neointimal formation.

Proximal bile duct stricture disguised as malignant neoplasm

BACKGROUND

Discrimination of malignant proximal bile duct (PBD) stricture from a benign lesion is difficult with nonsurgical methods; indeed, 8% to 13% of PBD strictures prove to be benign after histologic examination of the surgically resected specimen.

METHODS

In a 7-year period 178 patients with PBD stricture were admitted, and 99 of them underwent radical resection for presumably malignant lesions. In 14 of these patients the stenotic lesions were proved to be benign by postoperative histologic assessment. We reviewed these patients retrospectively by collecting data from their charts.

RESULTS

Preoperative radiologic findings including cholangiography and angiography were compatible with malignancy in all 14 patients. Preoperative histologic studies suggested malignancy in 2 of 8 examined. Findings at laparotomy could not allow differentiation between malignant and benign lesions in any of the patients and strongly suggested malignancy in 3. Histologic examination of the resected specimens revealed extensive fibrosis with inflammatory cellular infiltration in all patients. There was 1 episode of significant morbidity postoperatively (transient cholangitis) but no mortality.

CONCLUSION

Benign PBD strictures, although rare, are usually indistinguishable from malignant PBD strictures by preoperative or perioperative investigation. Given the minimal morbidity, all PBD strictures should be presumed malignant and managed accordingly, even at the risk of overtreating some benign cases.

[Selective and unselective clamping in liver surgery]

Liver surgery requires a reduction in the operative blood loss to avoid postoperative liver failure. We carried out elective hepatic resection in 229 patients with Pringle's maneuver, which involves complete, intermittent clamping of the hepatic flow, and in 56 patients with selective vascular occlusion. Twenty-seven donors for living-related liver transplantation were also included in the latter series. The clinical outcomes were evaluated based on clamping method used. The cumulative clamping time and amount of blood loss were 64 +/- 46 min (mean +/- SD) and 828 +/- 665 ml in the Pringle's maneuver group and 88 +/- 44 min and 907 +/- 555 ml in the selective vascular occlusion group. Laboratory data showed good tolerance of vascular clamping in both groups, and serum aspartate aminotransferase levels returned to the baseline within one week. Operative morbidity rates were 23% and 27%, respectively, and no operative deaths occurred in this series. In living-related liver transplantation, modified selective vascular occlusion can preserve graft viability, as verified by the fact that all the recipients in this series had a good postoperative course, except for one death and one graft loss. In conclusion, intermittent total or selective vascular clamping is indispensable procedure during hepatic resection.

Proximal bile duct stricture caused by a pancreatic pseudocyst: intra-operative placement of a metallic stent

A 61 year-old man presented with a proximal bile duct stricture caused by a pancreatic pseudocyst, which is of rare occurrence. Although it could not be determined pre-operatively whether the lesion was caused by cholangiocarcinoma or inflammatory disease, a laparotomy revealed that the proximal extrahepatic bile duct was surrounded and constricted by a pancreatic pseudocyst extending into the hepatoduodenal ligament. Since the stricture was not relieved only by removing the contents of the pseudocyst and surgical biliary diversion was considered too difficult, a self-expandable metallic stent was placed intra-operatively, at the strictured site, under ultrasonic guidance, via the transhepatic approach. The post-operative course of the patient was uneventful, and he remains well 22 months after the operation. The intra-operative placement of a metallic stent into the biliary tract can be an alternative option in the relief of biliary obstruction.

Tumor angiogenesis in gallbladder carcinoma

BACKGROUND/AIMS

Neovascularization of tumor tissue has been proposed to be essential for tumor growth, proliferation and, eventually, metastasis. Although the microvessel count in some kinds of solid tumor was shown to correlate with clinical outcome, little is known about its significance in gallbladder carcinoma.

METHODOLOGY

In order to determine whether tumor angiogenesis is a prognostic factor in gallbladder carcinoma patients, microvessels in selected areas (a 200x field, 0.74 mm2) in specimens resected from 40 patients with gallbladder carcinomas were identified by immunostaining endothelial cells for the endothelial antigen CD34 and counted.

RESULTS

Univariate analysis showed a relationship between the microvessel count and survival (p=0.04), but multivariate analysis revealed that the microvessel count was not an independent prognostic factor (p=0.256). Although it correlated with the lymph node status (p=0.044), it bore no relation to tumor status or clinical stage.

CONCLUSIONS

These results indicate that participation of neovascularization in gallbladder cancer spread is minor, especially during the early course.

A rare combination consisting of primary hyperaldosteronism and glucagonoma

A 59-yr-old man with multiple pancreatic tumors is presented. Previously, he had undergone left adrenalectomy for primary hyperaldosteronism and left nephrectomy for renal cell carcinoma at the ages of 39 and 55 yr, respectively. This time, 3 yr after removal of renal cancer, two solid lesions in the pancreas associated with hyperglucagonemia were detected. Under a diagnosis of pancreatic metastasis from renal cell carcinoma or islet cell tumor of the pancreas, distal pancreatectomy with splenectomy and enucleation of the tumor in the pancreas head were performed. Microscopically, a glucagonoma, measuring 2.3 mm in diameter, was detected among five pancreatic metastases from renal cell carcinoma. Four years after surgery, the patient remains well, without signs of recurrence despite multiple pancreatic metastases. This is the first report of such a rare combination consisting of aldosterone-secreting adrenal adenoma and glucagonoma.

Hepatic resection with and without surgical margins for hepatocellular carcinoma in patients with impaired liver function

BACKGROUND/AIMS

The significance of a surgical margin for hepatic resection of hepatocellular carcinoma (HCC) in patients with impaired liver function was evaluated.

METHODOLOGY

Sixty-eight patients, each with a solitary HCC, who had not received any prior treatments were divided into 2 groups, according to surgical margin: Group A included 25 patients who underwent resection with no margin (although the tumor was not exposed) and Group B included 43 patients with a sufficient surgical margin (mean distance: 9 mm). There were no significant differences in clinicopathologic variables between the 2 groups. The rate of stump recurrence, survival and recurrence-free survival were analyzed.

RESULTS

Among the 38 patients who had cancer recurrence after a median follow-up of 58 months, 9 (Group A, n=4; Group B, n=5) (24%) had recurrent lesions at the stump. The surgical margin was not a significant factor related to survival or recurrence, irrespective of cirrhosis, capsule formation, cancer spread, or tumor size.

CONCLUSIONS

Our results indicated that the HCC-free surgical margin is unlikely to be related to the survival of patients with impaired liver function unless the tumor is exposed on the raw liver surface.

Expression of the MAGE gene family in human hepatocellular carcinoma

BACKGROUND

The 12 members of the MAGE gene family encode tumor specific antigens that are recognized by autologous cytotoxic T lymphocytes (CTL). The MAGE genes are expressed not only in melanoma but in the other malignant tumors as well. There is, however, little information on their expression in hepatocellular carcinoma (HCC). The authors thus studied the expression of the MAGE gene family in human HCC and discuss the possibility of specific immunotherapy using MAGE peptides.

METHODS

Tumor tissue samples of HCC and paired nontumor tissues of the liver were obtained from 22 HCC patients. Total RNA was extracted and cDNA was synthesized. Polymerase chain reaction amplification using each MAGE gene specific primer was then performed to detect the expression of each MAGE gene. Immunoblotting and immunohistochemical analysis were performed to confirm the expression of MAGE-3 gene product in HCC.

RESULTS

The expression rate of each MAGE gene was as follows: MAGE-1 and -3 were expressed in approximately 68% of the tumors; MAGE-8 was expressed in 46%; and MAGE-2, -6, -10, -11, and -12 were expressed in approximately 30%. Nineteen (86%) of 22 tumors expressed at least 1 MAGE gene. On the other hand, no expression was detected in the noncarcinomatous liver tissue specimens. Actual expression of the gene product of MAGE-3 was detected in 50% of tumors. Clinicopathologic data on the MAGE positive and negative cases were compared. Significant differences were observed between MAGE expression status and a few clinicopathologic factors; however, further investigation is required to elucidate these correlations completely.

CONCLUSIONS

These findings demonstrated that MAGE gene expression is frequent in HCC, thus suggesting that HCC patients may be good candidates for specific immunotherapy using MAGE peptides.

Detection of Epstein-Barr virus (EBV) in hepatocellular carcinoma tissue: a novel EBV latency characterized by the absence of EBV-encoded small RNA expression

In this study, we investigated the presence of Epstein-Barr virus (EBV) in liver tissue from 35 patients with hepatocellular carcinoma (HCC). EBV DNA was detected in 13 patients (37%) by Southern blot hybridization. In 10 of these patients, EBV DNA was present in tumor tissue only, whereas in the other 3, it was detected in both tumor and nontumor tissues. The quantity of EBV DNA detected was equivalent to 1-10 viral DNA molecules/100 cells. EBV-determined nuclear antigen was detected in 7-13% of the carcinoma cells in three tumor tissue samples that contained approximately one copy of the EBV genome/10 cells. A single terminal fragment of EBV DNA was identified in these tissues, suggesting that the EBV-infected cells in HCC represent clonal proliferation. Western blotting and reverse transcription-polymerase chain reaction analyses demonstrated that these three tumor tissue specimens were positive for EBV-determined nuclear antigen 1 and BamHI A transcripts but were negative for the other latent EBV products, including EBV-encoded small RNA. The results indicated that there is a high EBV load in HCC tissue and that all of the HCC tissue examined showed a novel pattern of EBV latency characterized by absence of EBV-encoded small RNA expression.

Preoperative portal vein embolization: an audit of 84 patients

Preoperative portal vein embolization (PVE) was performed in 84 patients before extensive liver resection for various diseases. By the criteria of liver volumetric determination, some patients were candidates for PVE, whereas others were not, even though the same surgical procedure, such as extended right lobectomy (ERL), was scheduled. PVE using gelatin sponge powder induced hypertrophy in the nonembolized lobe (0%-171%; median, 30%) and proportional atrophy in the embolized lobe in 2 weeks without eliciting any major inflammatory or necrotic reaction, as evidenced histologically and by the minimal elevations in the serum aspartate transaminase (AST) and alanine transaminase (ALT) values. Alterations in the total bilirubin level and prothrombin time were also insignificant and transient, indicating that hepatocyte functions were not impaired by PVE. Not all patients who undergo PVE proceed with the scheduled hepatic resection procedure, so it is a great advantage that gelatin sponge causes minimal damage compared with other embolizing materials such as cyanoacrylate and absolute ethanol, which have been reported to induce an inflammatory reaction or histological alteration. Our multiple regression analysis showed that three factors, diabetes mellitus, a high total bilirubin level at the time of PVE, and being male, each reduced the extent of hypertrophy in the nonembolized lobe (r2 =.30). By contrast, cholestasis appeared to accelerate the process of atrophy in the embolized lobe (r2 =.16). In conclusion, PVE by gelatin sponge powder is a safe and effective preoperative maneuver that induces hypertrophy of the section of the liver that will remain after partial hepatectomy.

Evaluation of serum uric acid changes in different forms of hepatic vascular inflow occlusion in human liver surgeries

Uric acid values in serum have been analyzed as one of the markers to predict cellular damage due to ischemia reperfusion injury in the field of organ transplantation. The present study was conducted to confirm that uric acid values in serum could be an efficient marker of ischemic injury of liver parenchyma following hepatic vascular occlusion in human liver surgery. The changes in serum uric acid values were analyzed at fixed intervals during different liver surgeries. Significant increases in serum uric acid values were observed in patients who received the Pringle's maneuver in which hepatic vascular inflow was manipulated with a repetition of 15 min occlusion and 5 min perfusion, whereas almost no changes in uric acid values were found in both groups of patients who received the hemilobal occlusion of the Glisson's triad in which the right or left vessels were manipulated with a repetition of 30 min occlusion and 5 min perfusion and the "control method" in which the hepatic vessels of the lesion side were previously cut before liver resection. Uric acid values in serum increased in patients of Pringle's maneuver compared to those of the hemilobal occlusion of the Glisson's triad and the control method though these procedures were used in larger hepatectomies rather than Pringle's maneuver. The results indicated that serum uric acid values do not always reflect the severity of ischemia of the liver parenchyma but reflect intestinal congestion because marked intestinal congestion was observed in patients of Pringle's maneuver but not in patients of the hemilobal occlusion of the Glisson's triad and the control method. The evaluation of the severity of the ischemic injury of the liver should be done with caution when uric acid is used as a marker in human liver surgery.

Surgery of icteric-type hepatoma after biliary drainage and transcatheter arterial embolization

BACKGROUND/AIMS

The authors aimed to study the importance of pre-operative jaundice reduction in the surgical treatment of icteric-type hepatoma (IHCC).

METHODOLOGY

A series of 10 patients with IHCC was reviewed. Eight out of the 10 patients underwent biliary drainage. Obstructive jaundice in the other 2 patients resolved spontaneously. Nine patients subsequently underwent transcatheter arterial embolization (TAE), which appeared to have an additional effect in reducing jaundice.

RESULTS

Consequently, 9 of the 10 patients achieved sufficient reduction of the jaundice preoperatively. After the evaluation of liver function, 8 patients underwent hepatectomy without any appreciable morbidity or mortality. The median survival time of the resected cases was 18 months.

CONCLUSIONS

A combination of biliary drainage and subsequent TAE is a recommended pre-operative strategy for the successful surgical treatment of IHCC.

Surgical management for adrenal gland metastasis of hepatocellular carcinoma

BACKGROUND/AIMS

Although the adrenal gland is one of the common sites for metastasis from hepatocellular carcinoma, the significance of adrenalectomy for treatment of metastatic hepatocellular carcinoma still remains unclear.

METHODOLOGY

Analysis of 4 patients with adrenal metastasis from among 390 patients with hepatocellular carcinoma admitted to our department between October 1994 and December 1997, and a review of 79 cases reported between 1984 and 1997, were performed.

RESULTS

Four patients with adrenal metastasis, right in 2 and left in 2, underwent surgical treatment. Three of the patients developed tumor thrombi in the renal vein or inferior vena cava. Diagnosis of adrenal metastasis was made by ultrasonography or computed tomography scan, following an increase in serum tumor markers. Adrenalectomy with removal of the venous tumor thrombi was performed successfully. Three patients died of recurrence within 1 year, and one patient died due to other causes showing no recurrence at autopsy. The literature review revealed the left-sided metastases were significantly larger than the right-sided ones (p < 0.01). There was no significant difference in the survival periods between left and right metastasis, or between patients who underwent adrenalectomy and those treated by other means (p > 0.05).

CONCLUSIONS

The rationality of surgical treatment for adrenal metastasis from hepatocellular carcinoma still remains controversial. However, we believe that adrenalectomy would be a safe procedure and increases the chance of survival for patients.

Resection of peritoneal metastases from hepatocellular carcinoma

BACKGROUND/AIMS

To evaluate whether resection of peritoneal metastases arising from hepatocellular carcinoma (HCC) has a role to play in the management of the disease.

METHODOLOGY

Resections of peritoneal metastases from HCC were performed in 6 patients. The survival of the patients was evaluated in relation to feature of primary liver tumor, number of peritoneal metastases and period between hepatectomy and resection of peritoneal metastases.

RESULTS

Two patients had peritoneal metastases at the time of hepatectomy for HCC, their resection being carried out synchronously. In the other 4 patients, peritoneal metastases became evident between 6 and 34 months (mean: 18) after hepatectomy; resection was performed at the time of presentation of the metastases. Patient survival after resection of the peritoneal metastases ranged from 3-31 months. The 4 patients who survived for more than 1 year had the following features: 1) a small number of metastatic nodules (= or < 4); 2) low alpha-fetoprotein (AFP) values (mean: 205 ng/ml); and, (3) metachronous occurrence of the peritoneal metastases.

CONCLUSIONS

Resection of peritoneal metastases arising from HCC may be of value in improving patient survival.

Three generations of hereditary chronic pancreatitis

The patient was a 22 year-old male. Hereditary chronic pancreatitis was suspected as a diagnosis since his mother's uncle had been operated on for chronic pancreatitis 14 years previously at the age of 64 years and his mother had been operated on for chronic pancreatitis with calculi 5 years previously at the age of 40 years. Surgery was needed, since: 1) he had experienced abdominal pain for 8 years; 2) endoscopic retrograde cholangiopancreatography (ERCP) revealed a marked irregular dilatation in the main pancreatic duct and a marked irregular dilatation and protein plugs in the ductule of the tail of the pancreas; and, 3) pancreatic functional diagnostic (PFD) test examination showed a 75% decrease in exocrine function. If a surgical procedure had not been performed, the patient would likely have experienced calculi formation in the pancreas and a further decrease in exocrine function. Since the patient was very young and had many protein plugs in the dilated ductule of the tail of the pancreas, we decided to perform a spleen-preserving Puestow's procedure with removal of the tail of the pancreas. Clinical and pathological findings of hereditary pancreatitis are reviewed.

US guided biliary drainage during hepatopancreatico-jejunostomy for diffuse bile duct carcinoma

Liver failure is one of the principal causes of post-operative morbidity and mortality after major hepatectomy for diffuse bile duct cancer. To prevent this complication, biliary decompression must be guaranteed before and during the operation. If a nasobiliary catheter is positioned pre-operatively, biliary drainage can be maintained during hepatopancreato-duodenectomy by introducing a transhepatic drain under sonographic guidance. This original technique is described herein.

[Improving the anti-tumor activity of 5-fluorouracil by methotrexate]

The first clinical application of biochemical modulation (BCM) of 5-fluorouracil (5-FU) was the sequential MTX/5-FU regimen proposed in 1977 by Bertino for the treatment of colorectal cancer. In Japan, sequential MTX/5-FU therapy was mainly used as a new method of treating gastric cancer, and attracted a great deal of attention because it proved effective in many cases of advanced gastric cancer that had been unresponsive to the previous chemotherapy, particularly scirrhous gastric cancer with poor prognosis. Its therapeutic efficacy varied according to histologic type, it was effective in cases of peritoneal dissemination and disseminated intravascular coagulopathy (DIC), it was associated with fewer adverse effects, and it was a multidrug chemotherapy based on a clear rationale. With sequential MTX/5-FU therapy as a starting point, fundamental studies of BCM and its clinical applications have expanded rapidly in Japan. This paper provides an outline of sequential MTX/5-FU therapy from the aspects of its mechanism of action, indications, therapeutic efficacy, relevance to adjuvant therapy, counter-measures to adverse effects, and emergence of resistance to the drugs involved. The high therapeutic efficacy of this therapy in certain histologic types is also discussed, and its combined use with other forms of BCM, as in triple BCM (LV/5-FU + CDDP/5-FU + MTX/5-FU), is introduced.

Surgery for descending thoracic aortic anastomotic aneurysms with a temporary external bypass method

The surgical treatment of descending thoracic aortic anastomotic aneurysms is technically challenging. The purpose of this study was to evaluate the use of a temporary external bypass method as an intraoperative measure in the surgical treatment of anastomotic aneurysms of the descending thoracic aorta. An analysis of five consecutive patients who had undergone surgery for a collective seven descending thoracic aortic anastomotic aneurysms in our university hospital over a period of 14 years was conducted. A temporary bypass technique was used as an intraoperative measure in all the operations, four of which were performed with a right axillary to left external iliac artery bypass, while other sites were used in the remaining three. Systemic heparinization was able to be avoided in six operations and was markedly reduced in the remaining one. Although the major postoperative complication was coagulated hemothorax after six procedures, all patients recovered well and are still alive after a mean follow-up period of 8.2+/-1.5 (SEM) years. The results of this analysis led us to conclude that our temporary bypass method for treating descending thoracic aortic anastomotic aneurysm prevented the risks of anticoagulant administration for circulatory support, which contributed to the success of the operation. This method can be used as adjunct treatment for anastomotic aneurysms in the descending thoracic aorta.

Biologic significance of angiopoietin-2 expression in human hepatocellular carcinoma

Human hepatocellular carcinoma (HCC) is generally a highly vascular tumor, but the mechanisms of neovascularization that permit rapid growth have not been defined. Angiopoietins (Ang) recently have been identified as ligands for vascular endothelial-specific Tie2 receptor tyrosine kinase and may be important growth factors in the generation of new blood vessels. We investigated Ang expression in 23 samples of HCC and paired adjacent uninvolved liver samples to determine if these genes have a potential role in the growth and spread of this disease. The full coding sequence of a variant angiopoietin-2 (Ang2) cDNA was obtained from HCC specimens, and the biologic consequences of overexpression on tumor formation and hemorrhage were determined in an animal model system. Angiopoietin-1 (Ang1) was equally expressed in HCC and adjacent noncarcinomatous liver tissue. Surprisingly, Ang2 was found to be highly expressed only in tumor tissue. In addition, Ang2 was expressed in 10 of 12 hypervascular HCC, but only in 2 of 11 hypovascular HCC. Ectopic expression of Ang2 in nonexpressing HCC cells promotes the rapid development of human hepatomas and produces hemorrhage within tumors in nude mice. These results suggest a role for Ang2 in the neovascularization of HCC. This enhanced gene expression may contribute to the clinical hypervascular phenotype, as well as tumor formation and progression.