Heterogeneity in the nuclear DNA content of cells in carcinomas of the biliary tract and pancreas

Promoter hypermethylation of DAP-kinase is associated with poor survival in primary biliary tract carcinoma patients

To clarify the clinicopathological significance of promoter hypermethylation of tumor suppressor and tumor-related genes in biliary tract carcinomas, we examined the promoter methylation status of multiple genes in primary biliary tract carcinomas. These consisted of carcinomas of the bile duct, gallbladder, and duodenal ampulla. Surgical specimens were obtained from a total of 37 patients with biliary tract carcinoma. The cohort consisted of 23 patients with bile duct carcinoma, 9 patients with gallbladder carcinoma, and 5 patients with ampullary carcinoma. The methylation status of CHFR, DAP-kinase, E-cadherin, hMLH1, p16, RASSF1A, and RUNX3 was examined by methylation-specific polymerase chain reaction (MSP). The correlation between methylation status and clinicopathological characteristics was then assessed. The methylation frequencies of CHFR, DAP-kinase, E-cadherin, hMLH1, p16, RASSF1A, and RUNX3 genes were 16.2%, 21.4%, 27.0%, 8.1%, 24.3%, 27.0%, and 56.8%, respectively, in primary biliary tract carcinomas. The number of methylated genes per sample was 2.17 +/- 0.28 (average +/- SD) in bile duct carcinomas, 1.80 +/- 0.97 in ampullary carcinomas, and 0.89 +/- 0.35 in gallbladder carcinomas, with a statistically significant difference between bile duct carcinomas and gallbladder carcinomas (P = 0.02). As for clinicopathological significance, patients with a methylated RUNX3 promoter were significantly older than those with unmethylated RUNX3 (P = 0.01), and DAP-kinase methylation was more frequent in poorly differentiated tumors than in well to moderately differentiated ones (P = 0.04). The overall survival rate was significantly lower in patients with methylated DAP-kinase (P = 0.009) or RUNX3 (P = 0.034) compared to those with unmethylated genes. Furthermore, DAP-kinase methylation-positive status was independently associated with poor survival in multivariate analyses (hazard ratio = 8.71, P = 0.024). A significant proportion of primary biliary tract carcinomas exhibited promoter hypermethylation of tumor suppressor and tumor-related genes, although bile duct carcinomas are more prone to being affected by promoter methylation than are gallbladder carcinomas. Hypermethylation of DAP-kinase appears to be a significant prognostic factor in primary biliary tract carcinomas.

Prognostic value of cell proliferation (Ki-67 antigen) and nuclear DNA content in clinically resectable, distal bile duct carcinoma

BACKGROUND

The aim of this study was to investigate the prognostic value of cell proliferation (Ki-67 antigen) and DNA content in patients resected for distal bile duct carcinoma (DBDC).

METHODS

Formalin-fixed tumor specimens of 35 patients with resected DBDC and a long-term clinical follow-up were analyzed. MIB-1 antibody was used for Ki-67 antigen detection to determine the proportion of proliferating cells. DNA content was measured using flow cytometry.

RESULTS

A significant correlation was found between a low MIB-1 index (<20%) and survival (P <.05). Of the 35 tumor specimens, 34 specimens were evaluable by flow cytometry: 22 carcinomas were diploid (65%), and 12 were aneuploid (35%). The median DNA index of aneuploid tumors was 1.36 (range, 1.09 to 1.76). No correlation of DNA-ploidy with survival time was found.

CONCLUSION

In contrast to DNA-ploidy pattern, Ki-67 antigen expression showed prognostic significance in resectable DBDC. A Ki-67 positive ratio of > or =20% was associated with decreased survival time.

Establishment and characterization of a new transplantable pancreatic cancer xenograft (PZX-5) in immunosuppressed mice

CONCLUSION

A new, stable, transplantable human pancreatic cancer xenograft (PZX-5) model has been established in CBA immunosuppressed mice.

BACKGROUND

Numerous human pancreatic carcinomas have been successfully transplanted into athymic nude mice. However, artificially immunosuppressed animals have rarely been used as recipients. Because this model system proved to be reliable for hosting many human malignancies at our institute, successive xenotransplantations of a ductal adenocarcinoma have been carried out.

METHOD

Immunosuppression of CBA/CA mice was achieved by thymectomy, whole-body irradiation and bone-marrow reconstruction. Tumor fragments were subcutaneously implanted from a well/moderately differentiated ductal pancreatic adenocarcinoma and serially transplanted for more than 20 mo. The xenografted tumors were characterized using morphological, immunohistochemical, biochemical, and flow cytometric methods.

RESULTS

During the serial transplantations, the neoplasm maintained its original morphological-pathobiological characteristics. It produced a large amount of mucin and expressed carcinoembryonic antigen (CEA). Neither the mitotic activity nor the degree of differentiation was altered, and CEA was permanently detected. Flow cytometric DNA analysis revealed an aneuploid pattern (DNA index 1.45+/-0.03), which has remained within the same range during xenograftings. The doubling time in an in vitro system proved to be 18 h. The human character has been well preserved even 9 mo posttransplantation, as was evidenced by LDH-isoenzyme electrophoresis. The results indicate that the thymectomized--whole-body irradiated--bone-marrow reconstructed immunosuppressed mice are also appropriate hosts for pancreatic cancer xenografts.

The molecular genetics of pancreatic cancer

Pancreatic cancer is the fifth leading cause of cancer death in the United States, and despite improvements in the results of surgical treatment for this disease, little impact has been made upon overall mortality. New advances in treatment will depend upon improved adjuvant therapy, early diagnosis, and a better understanding of tumor biology. This article summarizes the results of molecular genetic studies in pancreatic cancer and their potential clinical significance. Familial predisposition to pancreatic cancer, cytogenic studies, DNA ploidy analysis, and examination of specific oncogenes and tumor suppressor genes are reviewed. The most frequent mutations detected have been in the K-ras oncogene, which occur in 80% of pancreatic cancers. These mutations do not correlate with tumor stage or survival, but can be useful in differentiating pancreatic exocrine from endocrine tumors and chronic pancreatitis. Mutations in the p53 gene occur in approximately 50% of tumors, and appear to be an independent prognostic factor for patient survival. Mutations in the CDKN2 gene are frequently seen in sporadic pancreatic cancers, and have been implicated in cases of familial pancreatic cancer. The significance of mutations in APC, MCC, DCC, c-erbB-2, RB-1, and mismatch repair genes in the genesis of pancreatic cancer is less clear.

DNA ploidy and S-phase fraction of neoplastic and non-neoplastic lesions of the human gallbladder

Studies on the cell kinetics of the human gallbladder are difficult because of epithelial degeneration by bile. Using the epithelial isolation technique, however, we were able to determine the degree of degeneration and to examine the cell kinetics of gallbladder lesions in freshly resected surgical specimens. Normal and neoplastic epithelia were isolated nonenzymatically from freshly resected gallbladder. The nuclear DNA content and S-phase fraction were estimated in 110 patients with gallbladder lesions by flow cytometry (FCM). Normal tissues and all lesions except carcinomas were diploid. The S-phase fraction of gallstone cases was significantly higher (1.47 +/- 0.70%; mean +/- SD) than normal (0.79 +/- 0.39%) (P < 0.0006). All gallbladder carcinomas were multiploid, and their S-phase fraction was 11.63 +/- 3.65%. Cell renewal of normal gallbladder is low. In the gallstone cases, the S-phase fraction was increased, possibly correlated with carcinogenesis.

DNA ploidy analysis of mucinous cystic tumors of the pancreas. Correlation of aneuploidy with malignancy and poor prognosis

BACKGROUND

Benign and malignant pancreatic mucinous tumors differ in proliferative activity, production of tumor markers, and expression of growth factors. DNA ploidy is a useful index of aggressiveness and poor survival in ductal adenocarcinoma, but has not been studied in pancreatic cystic tumors.

METHODS

The DNA ploidy status of Fuelgen-stained tissue sections of pancreatic mucinous cystic tumors was evaluated by image cytometry and related to clinical outcome obtained by case record review.

RESULTS

Ploidy status correlated with malignancy and poor clinical outcome. All benign mucinous cystadenomas (n = 13) were diploid and cured by resection. Patients with diploid cystadenocarcinomas (n = 6) had an 83% survival rate following resection, while patients with aneuploid cystadenocarcinomas (n = 5) all died (four of disease and the fifth of another cause). The difference in survival between the diploid and aneuploid carcinomas was significant (P = 0.04).

CONCLUSIONS

DNA ploidy status of pancreatic mucinous tumors by image analysis provides quantifiable information that may be predictive of clinical outcome. DNA aneuploidy appears to be a significant differential factor in pancreatic mucinous tumors and is associated with shortened survival in mucinous cystadenocarcinomas.

Combined use of nuclear morphometry and DNA ploidy as prognostic indicators in nonresectable adenocarcinoma of the pancreas

The introduction of combined modality treatment has only marginally affected the prognosis in nonresectable pancreatic carcinoma. Evaluation of easily accessible prognostic variables could be of clinical importance when selecting patients for proper therapy. DNA ploidy and morphometric variables were chosen as prognostic markers and assessed on cytologic material obtained by fine-needle aspiration biopsy (FNAB) from 128 patients with pancreatic carcinoma. The nuclear DNA content was measured by image cytometry. Patients were categorized as short-term (< or = 6 mo) and long-term survivors (> 6 mo). Ninety-eight of 116 nonresectable patients were possible to evaluate. There were significant differences between short- and long-term survivors with regard to DNA ploidy (p < 0.01) and the morphonuclear variable anisokaryosis (p < 0.001). In patients with either DNA aneuploid tumors or anisokaryosis > or = 0.6, the survival time was 6 mo or less in 85 and 93%, respectively. When both these criteria were fulfilled, only 5% survived for more than 6 mo. Thus, DNA ploidy and morphometry, separately or in combination, may provide prognostic information in nonresectable pancreatic carcinoma.

DNA analysis of in situ ductal carcinoma of the breast via flow cytometry

Flow cytometric (FCM) DNA analysis of 41 clinical cases of ductal carcinoma in situ (DCIS) of the breast was performed on fine-needle aspirates of unfixed, frozen tissue. Based on analysis of a single tissue sample, abnormal DNA content was found in 35 (85%) of the cases, and 15 (37%) disclosed heterogeneity. If five or more samples were analyzed, then heterogeneity was found in eight of ten cases. No conclusive correlation could be found between DNA index (DI) and histopathology. Our results on DCIS demonstrate a very high concordance with invasive breast cancer with respect to the frequency of DNA nondiploid cases, distribution of DI, occurrence of multiple clones, and S-phase fraction. This indicates that major genetic alterations and DNA heterogeneity are early events in carcinogenesis that are already established at the preinvasive stage.

Cytogenetic heterogeneity and histologic tumor growth patterns in prostatic cancer

Twenty-five prostatic adenocarcinomas were studied for the presence of intratumoral cytogenetic heterogeneity by interphase in situ hybridization (ISH) to routinely processed tissue sections. ISH with a chromosome Y-specific repetitive DNA probe provided a model to investigate patterns of chromosomal heterogeneity within and between different pathological grades. The Gleason grading system was used, since it is based on a detailed classification of growth patterns. Heterogeneity with respect to ploidy of the tumor was examined by ISH with a repetitive DNA probe specific for chromosome 1. The ploidy status of these cancers was confirmed by DNA flow cytometry (P < 0.001). Cytogenetic heterogeneity at the (Y) chromosomal level was observed between Gleason areas, within one area, and even within single tumor glands. The different patterns of chromosomal heterogeneity were seen in all tumor grades and stages. Differences in ploidy status were also found following the aforementioned histological patterns, again, in all grades and stages. Intraglandular heterogeneity was most frequently seen. No correlation was found between cytogenetic heterogeneity and proliferative activity (Ki-67 immunostaining). In contrast to current views on clonality, suggesting regional separation of subclones with different DNA content, this study demonstrates that these subclones can be interspersed.

Acute-phase protein response and survival duration of patients with pancreatic cancer

BACKGROUND

Current methods to predict survival duration of patients with pancreatic cancer are limited. The aim of this study was to determine whether certain nutritional indices and the acute-phase protein response are prognostic factors independent of disease stage for patients with unresectable pancreatic cancer.

METHODS

Variables at the time of diagnosis of 102 patients with unresectable pancreatic cancer were entered into a Cox's proportional hazards model. Included in the analysis were the serum concentration of C-reactive protein (CRP) and albumin, the extent of weight loss, age, sex, and disease stage (International Union Against Cancer criteria).

RESULTS

A multivariate analysis in which each factor was adjusted for the influence of the other factors revealed the patient age, disease stage, serum albumin, and serum CRP to be independent predictors of survival. The presence of an acute-phase protein response was the most significant independent predictors of survival duration. The median survival of those with an acute-phase protein response (CRP > 10 mg/L, n = 45) was 66 days compared with 222 days for those with no acute-phase protein response (n = 57, P = 0.001, Mann-Whitney U test).

CONCLUSION

The acute-phase protein response is a useful prognostic indicator for patients with unresectable pancreatic cancer. Moreover, the metabolic disturbances associated with an acute-phase protein response of patients with pancreatic cancer may be a worthwhile therapeutic target.