A.K.K Chui

Mutation of p53 in Recurrent Hepatocellular Carcinoma and Its Association with the Expression of ZBP-89

p53 has recently been identified as a downstream target of ZBP-89, a zinc finger transcription factor. ZBP-89 promotes growth arrest through stabilization of the p53 protein. The aim of this study is to determine the status of the p53 gene in recurrent human hepatocellular carcinoma (HCC) and test the link between the expression of ZBP-89 and the p53 gene. The results showed that mutations in the p53 gene were frequently detected in recurrent HCC. The interval between surgical resection and the recurrence of HCC was significantly longer in patients with the wild-type p53 gene than those with mutations, strongly suggesting a pathological role for the mutant p53 gene in HCC recurrence. Among those positive for the p53 protein, nearly 85% (18 of 21) showed nuclear localization of the p53 protein while only about 14% (3 of 21) were positive for the p53 protein in the cytoplasm. ZBP-89 co-localized with p53 in the nucleus in about 67% (12 of 18) of all cases positive for the nuclear p53 protein, suggesting that ZBP-89 may play a role in the nuclear accumulation of the p53 protein in a subset of recurrent HCC. With accumulation of p53 protein in the nucleus, tumor cells undergo apoptosis and thus are more susceptible to radiotherapy and chemotherapy. Therefore, co-localization of p53 protein with ZBP-89 may define a subgroup of recurrent HCC that is more sensitive to treatment.

Outcome of lamivudine resistant hepatitis B virus mutant post-liver transplantation on lamivudine monoprophylaxis.

Abstract:  Background:  We aimed to investigate the clinical outcome of patients who develop lamivudine resistant hepatitis B virus mutants (YMDD mutants) after liver transplantation.

Activation of kupffer cells inhibits tumor growth in a murine model system

Kupffer cells, a liver organ‐specific macrophage, play an important role in preventing the development of malignant tumors. The mechanism responsible for their tumoricidal activities is not completely known. In our study, we established in vivo models involving a rat malignant cell line, rat Kupffer cells and tumor implantation in nude mice. A series of relevant in vitro experiments were also carried out to determine possible pathways. LPS‐activated Kupffer cells produced significant amounts of NO, TNFα and IFNγ. Malignant cells treated with either Kupffer cells or culture supernatant of the activated Kupffer cells had an increase in caspase‐8 activity. Implanted tumors originated from malignant cells treated with either Kupffer cells or culture supernatant of the activated Kupffer cells grew much smaller than those from malignant cells without treatment or treated with control supernatants. The alteration of anti‐apoptotic Bcl‐2 was inversely associated with the change of pro‐apoptotic caspase‐8 and their levels in the tumor tissues matched the size of the tumors and treatments they received. It appeared that the above changes resulted in an increase in cellular DNA damage and apoptosis seen in malignant cells. Therefore, Kupffer cells execute their anti‐tumor effect via increasing the production of NO, TNFα and IFNγ and these cytotoxic molecules inhibit the growth of tumor by damaging cellular DNA and inducing apoptosis that was featured by downregulation of Bcl‐2 but upregulation of caspase‐8.

An active liver transplant programme for hepatocellular carcinoma in cirrhotic patients : is it justified?

Even at an early stage, hepatocellular carcinoma (HCC) in patients with cirrhosis is often deemed unresectable because of limited liver reserve. In these circumstances, liver transplantation (LTx) offers some hope for palliation or cure. The results of LTx for selected cirrhotic patients with HCC were analysed. The outcomes were compared with those of patients who underwent LTx for other forms of hepatic malignancy and those who underwent LTx for non‐malignant conditions. Four hundred and eighty LTx were performed in 441 patients between January 1986 and December 1998. Twenty‐eight LTx recipients (25 males, 3 females) of mean age 51 (14–63) yr had cirrhosis and HCC. Twenty‐seven patients had underlying predisposing conditions (11 had hepatitis B, 10 had hepatitis C, 2 had hepatitis B and C, 1 had haemochromatosis, 1 had autoimmune hepatitis, 1 had alcoholic cirrhosis and 1 had α‐1 antitrypsin deficiency). In 22 patients, HCC was diagnosed pre‐LTx, and in 6 patients, the cancers were discovered incidentally. The average tumour size and number were 2.8 (0.4–11.5) cm and 1.3 (1–4), respectively. Two patients with known HCC died during and shortly after the LTx operation. Of the other patients, 3 died; 1 died of HCC recurrence 18 months post‐LTx, 1 died of graft failure from recurrent hepatitis C and 1 died of fungal sepsis. Twenty‐three (82%) patients survived to 22.5 (0.5–96) months post‐LTx without HCC recurrence and with 1‐ and 3‐yr actuarial patient survival rates of 87 and 76%, respectively. Equivalent survival rates of patients who underwent LTx for other malignancies (n=11) were 82 and 46% (p=NS), and for those who underwent LTx for benign causes (n=402), they were 77 and 73% (p=NS). All 15 patients with known HCC, who met the selection criteria now in use, survived. LTx can result in prolonged, cancer‐free survival in a good proportion of patients with cirrhosis and HCC, particularly when the cancers are incidental, or when diagnosed pre‐LTx, conforming to established selection criteria. An active LTx programme for this group of patients is justified.

Does patient position during liver surgery influence the risk of venous air embolism

BACKGROUND It is generally believed that positioning of the patient in a head-down tilt (Trendelenberg position) decreases the likelihood of a venous air embolism during liver resection. METHODS The physiological effect of variation in horizontal attitude on central and hepatic venous pressure was measured in 10 patients during liver surgery. Hemodynamic indices were recorded with the operating table in the horizontal, 20 degrees head-up and 20 degrees head-down positions. RESULTS There was no demonstrable pressure gradient between the hepatic and central venous levels in any of the positions. The absolute pressures did, however, vary in a predictable way, being highest in the head-down and lowest during head-up tilt. However, on no occasion was a negative intraluminal pressure recorded. CONCLUSION The effect on venous pressures caused by the change in patient positioning alone during liver surgery does not affect the risk of venous air embolism.

Simultaneous Detection of Precore/Basal Core Promoter Mutations in Hepatitis B Virus Using Arrayed Primer Extension

AbstractBackground: Hepatitis B is a major disease that causes serious public health problems worldwide. The loss of HBeAg expression due to point mutations or single nucleotide polymorphisms (SNPs) in the precore/basal core promoter region of the hepatitis B virus (HBV) is associated with hepatocellular cirrhosis and carcinoma. Simultaneous screening for these mutations is strongly advocated for monitoring disease development in HBV-infected patients. The aim of this study is to apply arrayed primer extension (APEX) for the detection of HBV SNPs at the precore/basal core promoter. Methods and results: We optimized APEX for simultaneous detection of eight potential sites of SNPs in the precore/basal core promoter region of HBV. The precore/basal core promoter regions of HBV from 36 HBV-infected patients were amplified by PCR. After purification and DNA fragmentation, the short, single-stranded HBV DNA fragments were allowed to hybridize with the oligonucleotides corresponding to the sites of SNPs immobilized on glass slides, followed by incorporation of different fluorescently labeled dideoxynucleotides. This allows fast and unequivocal discrimination between wild-type and mutant genotypes with high dideoxy-nucleotide incorporation efficiency, sensitivity, and specificity. The coexistence of both genotypes was also detected; this was undetected by DNA sequencing. Conclusion: The simultaneous detection of SNPs in HBV precore/basal core promoter by APEX enables large-scale diagnostic analysis, which can be extended to the whole HBV genome.