Choong-Tsek Liew

Assessment of Genetic Changes in Hepatocellular Carcinoma by Comparative Genomic Hybridization Analysis : Relationship to Disease Stage, Tumor Size, and Cirrhosis

Hepatocellular carcinoma (HCC) is a common and highly malignant tumor that is prevalent in Southeast Asia. Although the etiological factors associated are now well recognized, the interactions between individual factors and the molecular mechanisms by which they lead to cancer remain unclear. Cytogenetic analysis on HCC has been limited because of poor hepatocyte growth in vitro. The recently developed technique of comparative genomic hybridization (CGH), however, permits screening of the entire genome without the need of cell culture. CGH was applied to the study of genomic aberrations in 67 surgically resected samples of HCC, 3 of adenomatous hyperplasia (AH), and 12 of nontumorous cirrhotic liver surrounding the tumors. All samples were from patients of a racially and etiologically homogeneous population in Southern China, where chronic hepatitis B virus infection is the main etiological factor. CGH analysis of the HCC samples revealed frequent copy number gain of 1q (48/67 cases, 72%), 8q (32/67 cases, 48%), 17q (20/67 cases, 30%), and 20q (25/67 cases, 37%) and common losses on 4q (29/67 cases, 43%), 8p (25/67 cases, 37%), 13q (25/67 cases, 37%), and 16q (20/67 cases, 30%). Our finding of a high incidence of 1q gain strongly suggested this aberration was associated with the development of HCC. Genomic abnormalities were detected in 1 of the 3 AH specimens but absent in all 12 cirrhotic tissues surrounding the tumor. Clinical staging classified 3/67 HCC cases as T1, 53 cases as T2, and 11 cases as T3. No significant difference in the pattern of genomic imbalances was detected between stages T2 and T3. A significant copy number loss of 4q11-q23 was, however, identified in those tumors larger than 3 cm in diameter. Of particular interest was the identification of 8q copy number gain in all 12 cases of HCC that arose in a noncirrhotic liver, compared with only 20/55 cases in HCC arising in a cirrhotic liver. We suggest that 8q over-representation is likely associated with a growth advantage and proliferative stimulation that have encouraged malignant changes in the noncirrhotic human liver.

Identification of Chronic Hepatitis B Patients without Significant Liver Fibrosis by a Simple Noninvasive Predictive Model

OBJECTIVE:Histological assessment of liver fibrosis is important in the management of chronic hepatitis B (CHB) infection but poorly accepted by patients because of its invasiveness. The aim of this study was to develop a noninvasive model to assess liver fibrosis in CHB patients using clinical and routine laboratory data.PATIENTS AND METHODS:This was a retrospective study on 235 treatment-naïve viremic CHB patients. Univariate analysis of data from the training cohort (n = 150) followed by multivariate logistic regression were performed to identify independent predictors of significant fibrosis and generate predictive models. The models were validated with the remaining patients or validation cohort (n = 85) and by receiver operating characteristics (ROC) analysis.RESULTS:Body mass index (BMI), platelet count, serum albumin, and total bilirubin levels were identified as independent predictors of bridging fibrosis or cirrhosis (Ishak stage 3–6). ROC analysis was performed using the predictive probabilities derived from the regression models. The area under the ROC curve of the best model was 0.803 (95% CI: 0.729–0.878) for the training cohort, 0.765 (95% CI: 0.644–0.885) for the validation cohort, and 0.791 (95% CI: 0.728–0.854) for the entire cohort. Using the low cut-off probability of 0.15, significant fibrosis could be excluded in 83 patients of the total patient population (negative predictive value 0.92).CONCLUSIONS:Our noninvasive model comprising BMI and three routine laboratory tests was accurate in predicting absence of significant fibrosis. Application of this model could provide useful additional information on the stage of disease, guide future management decisions, and potentially decrease the need for liver biopsy in some CHB patients.

Salvage Surgery Following Downstaging of Unresectable Hepatocellular Carcinoma

Objective:We reported here a series of 49 patients with unresectable hepatocellular carcinoma (HCC) who underwent nonsurgical treatment to downstage the disease followed by salvage surgery, their long-term outcome, and pattern of recurrence. Summary Background Data:Most HCC patients present with unresectable disease and are treated with chemotherapy or intra-arterial therapy with a palliative intent. Occasionally, there are good responses to treatment so that salvage surgery becomes feasible afterward. However, long-term outcomes of these patients are seldom reported. Methods:Patients with unresectable hepatocellular carcinoma, from September 1993 to June 2002, who received salvage surgery after downstaging by systemic chemotherapy, intra-arterial yttrium-90 microspheres, or sequential treatment were included in this study. Systemic chemotherapy consisted of combination doxorubicin, cisplatin, interferon-alpha and 5-fluorouracil (5-FU), or single-agent doxorubicin. The choice of treatment was according to stage of disease and contemporary clinical trial protocol. Survival, recurrence pattern, and surgical outcome were studied. Results:There were 49 patients in this study with 40 males and 9 females, age ranged from 12 to 69 years. Forty patients (81.6%) were hepatitis B positive. Thirty-two patients had combination chemotherapy alone (65.3%), 8 patients had single agent chemotherapy alone (16.3%), 4 patients received intra-arterial yttrium-90 microspheres alone (8.2%), and 5 patients received sequential therapy (10.2%). Twenty-eight (57.1%) patients received major hepatic resection. Thirteen patients (26.5%) had complete necrosis of the tumor after treatment. Twenty-one patients (42.9%) had recurrence after surgery, and 14 of them were intrahepatic recurrence. The median survival was 85.9 months. The 1-year, 3-year, and 5-year survival rates were 98%, 64%, and 57%, respectively. Conclusions:Salvage surgery after successful downstaging can provide long-term control of disease in a small proportion of patients with unresectable hepatocellular carcinoma.

Differential gene expression of hepatocellular carcinoma using cDNA microarray analysis.

A cDNA microarray technique, which allows simultaneous analysis of differential expression of mRNA of over 4000 known human genes, was utilized to study the gene expression in 10 pairs of HCC and nontumorous tissues from ethnic Chinese patients in Hong Kong. A total of 211 genes were found to be highly expressed and 147 genes were downregulated in more than 1 out of 10 of the HCC pairs. The results were significant by two-tailed Wilcoxon test (P < or = 0.05 with 95% confidence) on the intensity of each DNA spot of the 10 HCC pairs. Six genes were highly expressed and 10 genes were downregulated in more than 30% of HCC pairs. Results are consistent with other published reports using traditional differential display, subtractive hybridization, or immunohistochemical staining methods. We also detected that beta-actin and glyceraldehyde 3-phosphate dehydrogenase (G3PDH), which have been commonly used as an internal standard control in mRNA expression studies, were highly expressed in HCC when compared with nontumorous tissue. It is concluded that cDNA microarray analysis is an effective method in the detection of differential gene expression in HCC.

Positional mapping for amplified DNA sequences on 1q21–q22 in hepatocellular carcinoma indicates candidate genes over-expression

BACKGROUND/AIMS Comparative genomic hybridization analysis on hepatocellular carcinoma (HCC) indicated frequent gains of 1q and an amplicon at 1q21-q22. Current cytogenetic evidences confer much importance on 1q21-q22, where a role in drug resistance, tumor metastasis and shorter patient survival had been implicated. METHODS Using positional mapping by interphase cytogenetics, we investigated the amplicon 1q21-q22 in five HCC cases. Three amplification maxima represented by yeast artificial chromosomes (YACs) 955E11, 876B11 and 945D5 that mapped to regions 1q21.1, 1q21.2 and 1q22, respectively, were indicated. We further investigated candidate genes expression in the mapped YACs by quantitative reverse-transcription-polymerase chain reaction. A panel of genes encoding protein transcripts involved in apoptosis, cell cycle progression, calcium binding and jumping translocation was studied. RESULTS Among ten HCC cases with the amplicon 1q21-q22 examined, we found a significant gene expression level of JTB, SHC1, CCT3 and COPA in the tumors than the paired adjacent non-malignant liver tissues (P< or =0.04). CONCLUSIONS Our interphase findings on 1q21-q22 pinpointed three affected loci between D1S305 and D1S2369. Up-regulation of candidate genes identified within these over-represented regions may represent targets in the progression of HCC and may carry prognostic significance.

Preoperative Systemic Chemoimmunotherapy and Sequential Resection for Unresectable Hepatocellular Carcinoma

ObjectiveTo examine the surgical and pathologic findings of 15 patients who had initially unresectable hepatocellular carcinoma (HCC) and received preoperative systemic chemoimmunotherapy and sequential resection. Summary Background DataMore than 80% of patients with HCC present for treatment at an unresectable stage. Conventional treatment has produced a low tumor response rate in this group of patients. Recently, new systemic chemoimmunotherapy has been found to be effective and able to make previously unresectable HCC resectable. Sequential resection after response to chemoimmunotherapy could therefore induce complete clinical remission. MethodsFrom July 1996 to February 1999, 150 patients with unresectable HCC were treated with systemic chemoimmunotherapy consisting of cisplatin, &agr;-interferon, doxorubicin, and 5-fluorouracil for a maximum of six cycles. The residual tumors were reassessed for resectability after treatment aiming at complete remission in the patients after combined modality treatment. Twenty-seven patients had a more than 50% regression in tumor size (2 complete remissions, 25 partial remissions). Fifteen patients had resectable disease after treatment, and all underwent sequential resection with curative intent. Treatment outcome and the surgical and pathologic features of these 15 patients were studied. ResultsFifteen of 150 patients responded to chemoimmunotherapy and underwent sequential resection. They were considered to have unresectable disease as a result of extensive local disease (with and without major vascular involvement) in 10 patients and the presence of extrahepatic or metastatic disease in 5 patients. All patients except two were hepatitis B carriers. Surgical resection of the residual lesion after chemoimmunotherapy was successful for all patients. Eight of the patients had complete pathologic remission. The rest had minimal residual disease (<5%) only. All 15 patients entered complete clinical remission after surgery. Thirteen patients were still alive as of this writing and two had died of recurrent disease. The 1-, 2-, and 3-year survival rates were 100%, 100%, and 53%, respectively. The mean follow-up period was 27 months (range 15–37). Neither the median disease-free nor overall survival had been reached. Ten patients remained in complete remission as of this writing. ConclusionCombined modalities with systemic chemoimmunotherapy and surgical resection can achieve complete clinical remission and long-term control of disease in patients with unresectable HCC.

Quantitative assessment of fibrosis in liver biopsies from patients with chronic hepatitis B

Abstract: Background/aim: Accurate histological assessment of liver fibrosis is essential in the management of chronic hepatitis B (CHB). Although semi‐quantitative scoring systems describe well the pathological patterns of hepatic structure, they produce fibrosis evaluation that is not very precise. Image analysis or morphometry has the theoretical advantage of providing truly quantitative data.

Identification of Four Distinct Regions of Allelic Imbalances on Chromosome 1 by the Combined Comparative Genomic Hybridization and Microsatellite Analysis on Hepatocellular Carcinoma

Frequent chromosome 1 abnormalities detected in human hepatocellular carcinoma have been implicated in early genetic events of liver carcinogenesis. Recurrent loss of 1p with a common deleted region 1p36–p34 has been reported from microsatellite analysis, whereas common gain of the whole chromosome q-arm was described from several comparative genomic hybridization studies. The relationships between copy number changes and allelic status however remains unclear. In this study, we have conducted a simultaneous comparative genomic hybridization and microsatellite analysis study on chromosome 1 in 31 hepatocellular carcinoma cases. Microsatellite analysis revealed frequent loss of heterozygosity on 1p at loci D1S468 (74%), D1S450 (67%), D1S2667 (65%), D1S2697 (75%), D1S199 (52%), and D1S234 (67%) corresponded to the distal 1p36 region and coincided with 12 cases (86%) that presented losses on 1p by comparative genomic hybridization analysis. Although comparative genomic hybridization indicated a common deleted region of 1p36–p35 in the current series, microsatellite analysis has refined the smallest overlapping region (SOR) to 1p36.13–p36.22. Gain of 1q as revealed by comparative genomic hybridization suggested low and high-level gains, and cases that displayed an amplicon below the heterochromatic region 1q21–q25. Common allelic imbalances of polymorphic markers D1S2635 (64%), D1S484 (67%), D1S2878 (65%), D1S196 (70%), D1S249 (64%) D1S2785 (75%), D1S2842 (73%) and D1S2836 (74%) that corresponded to the regions 1q23.1–q24.2, 1q32.1 and 1q43–q44 were detected. Three distinct regions of allelic imbalances were thus suggested on recurring 1q gain found in hepatocellular carcinoma. Furthermore, microsatellite analysis has enabled a mapping of common overrepresented regions and suggested SOR on 1q23.1–q23.3 (D1S2635-D1S2878), 1q25.1–q31.1 (D1S452-D1S238), and 1q43 (D1S2785-D1S2842). Our current study has refined chromosome 1 aberrations in hepatocellular carcinoma to four regions of allelic imbalances. The SORs delineated should provide basis for further molecular investigation in hepatocarcinogenesis on genes residing on these chromosomal regions.

Pre-operative induction chemotherapy for small cell carcinoma of the oesophagus: a case report.

Induction chemotherapy was prescribed to a patient who had locally advanced small cell carcinoma of the oesophagus which was considered to be irresectable on presentation. Significant tumour downstaging was observed and the patient remains recurrence free 16 months after a successful Ivor-Lewis oesophagectomy.