Osamu Ishikawa

Genome-wide cDNA microarray analysis of gene expression profiles in pancreatic cancers using populations of tumor cells and normal ductal epithelial cells selected for purity by laser microdissection

To characterize molecular mechanism involved in pancreatic carcinogenesis, we analysed gene-expression profiles of 18 pancreatic tumors using a cDNA microarray representing 23u2009040 genes. As pancreatic ductal adenocarcinomas usually contain a low proportion of cancer cells in the tumor mass, we prepared 95% pure populations of pancreatic cancer cells by means of laser microbeam microdissection, and compared their expression profiles to those of similarly purified, normal pancreatic ductal cells. We identified 260 genes that were commonly upregulated and 346 genes that were downregulated in pancreatic cancer cells. Because of the high degree of purity in the cell populations, a large proportion of genes that we detected as upregulated or downregulated in pancreatic cancers were different from those reported in previous studies. Comparison of clinicopathological parameters with the expression profiles indicated that altered expression of 76 genes was associated with lymph-node metastasis and that of 168 genes with liver metastasis. In addition, expression levels of 30 genes were related to the recurrence of disease. These genome-wide expression profiles should provide useful information for finding candidate genes whose products might serve as specific tumor markers and/or as molecular targets for treatment of patients with pancreatic cancer.

Diagnosis of intrahepatic metastasis and multicentric carcinogenesis by microsatellite loss of heterozygosity in patients with multiple and recurrent hepatocellular carcinomas

BACKGROUND/AIMSnThe prognosis of hepatocellular carcinoma (HCC) is poor because of frequent intrahepatic metastasis (IM) or multicentric carcinogenesis (MC). We compared the effectiveness of loss of heterozygosity (LOH) analysis in the diagnosis of these two forms with that of histopathological diagnosis.nnnMETHODSnUsing LOH analysis of 15 specific DNA microsatellite loci, tumor clonality was assessed in 37 cases.nnnRESULTSnLOH was observed in 30% of seven solitary tumors. According to these results, the selected threshold to diagnose MC was a difference in the LOH status at more than 30% of the analyzed loci, when comparing two samples in the same liver. In nine multiple HCCs, identical genetic and histopathological diagnoses were found in four (IM: 2, MC: 2). Of 21 recurrent tumors, 19 showed LOH for at least one marker. IM and MC were genetically diagnosed in five and ten patients, respectively. Genetic and histopathological diagnoses were identical in ten of 19 patients (IM: 5. MC: 5). Five genetic MC were histopathologically diagnosed as IM (3) and undetermined (2).nnnCONCLUSIONSnGenetic diagnosis by LOH analysis may be more strict and specific than histopathological diagnosis in the differential diagnosis of IM and MC.

Adenosquamous carcinoma of the pancreas: A clinicopathologic study and report of three cases

Among 27 surgically resected carcinomas of the pancreas, 3 cases were diagnosed histologically as adenosquamous carcinoma (11.1%). This is the highest rate among the medical literature we reviewed. Since a very small focus of squamous cell carcinoma was detected through close observation in 1 case, it would seem that this sort of pancreatic tumor could be more common than is ordinarily expected. From the histologic studies of these 3 cases, it seems likely that the preexisting adenocarcinoma partially underwent malignant transformation into a malignant squamous component. When the different modes of spread of these two histologic elements are compared, the adenocarcinomatous element seems to be more invasive and more likely to metastasize than does squamous cell carcinoma.

Association of p53 gene mutations with short survival in pancreatic adenocarcinoma

Mutations of the p53 gene have been found in a variety of human cancers and are implicated in the biologic functions of cancer. To investigate the clinical implications of p53 mutations in pancreatic adenocarcinoma, we examined the association of mutations of the p53 gene with patients’ prognosis. Single‐strand conformational polymorphism analysis and direct DNA sequencing were used to detect p53 gene mutations in 37 pancreatic adenocarcinomas. p53 gene mutations were detected in 16 (43%) of the 37 pancreatic adenocarcinomas. Direct sequencing did not reveal preferential clustering at any specific codon. There was no significant association of the presence of p53 gene mutations with histologic types, extent of tumor invasion, the presence of lymph node metastasis, or tumor stage. Univariate analysis showed that survival of patients with p53‐gene‐mutation tumors was significantly poorer than that of patients with p53‐gene‐nonmutated tumors (p=0.02). Coxs multivariate analysis of ten clinicopathologic features including p53 gene mutations revealed that presence of p53 gene mutations (p= 0.026) and curativity of operation (p=0.014) were independent predictors of survival. Furthermore, the survival of patients with p53‐gene‐mutated tumor was significantly poorer than that of patients with p53‐gene‐nonmutated tumors, both in patients who underwent curative operation (p=0.04) and in patients who underwent non‐curative operation (p=0.01). These results suggested that mutations of the p53 gene might play an important role in cancer aggressiveness and could be a clinically useful predictor of prognosis in patients with pancreatic adenocarcinoma.

Expression of autocrine motility factor receptor in colorectal cancer as a predictor for disease recurrence

Background. New biologic prognostic factors are needed to guide the treatment of patients with colorectal cancer. The prognostic value of the altered expression of the cell surface glycoprotein gp78, which has been implicated in tumor‐cell invasion and metastasis as an autocrine motility factor (AMF) receptor, was evaluated.

Coexistence of bilateral pheochromocytoma and pancreatic islet cell tumor. Report of a case and review of the literature

A 14‐year‐old Japanese male with a previously undescribed combination of bilateral pheochromocytoma and an islet cell tumor of the pancreas is presented. The combination of endocrine neoplasms in this patient overlaps multiple endocrine neoplasia (MEN) Type 1 and Type 2. A total of 14 reported cases of MEN overlapping Type 1 and Type 2 is reviewed. Of the 14, 7 patients with acromegaly developed a paraganglioma(s), 2 patients with Sipple syndrome had a pituitary adenoma, and in the other 5 patients, an intestinal carcinoid or a pancreatic islet‐cell tumor occurred in association with either a thyroid medullary carcinoma or a paraganglioma(s). We believe that the occurrence of MEN overlapping Type 1 and Type 2 is more than a fortuitous association, and can be explained on the basis of the neuroectodermal origin. Cancer 42:2928–2934, 1978.

Carcinoid tumor of the gallbladder associated with adenocarcinoma.

A case of carcinoid tumor of the gallbladder associated with adenocarcinoma in a 56‐year‐old man is reported and a review of the literature is made. The tumor was a polypoid mass with a size of 5.5 × 4.0 × 2.8 cm. Histologically, the tumor showed carcinoid and adenocarcinoma with areas of mucous change. Tumor cells containing argyrophil granules were observed in both carcinoidal and adenocarcinomatous areas, but no argentaffin granules were detected in either of the neoplastic areas. Some of the tumor cells had both argyrophil granules and mucin in the same cytoplasm. The electron microscopic study revealed several tumor cells containing neurosecretory granules; however, no clinical signs of hormonal activities of the tumor were observed. The patient died of generalized bone metastases 16 months after surgery. This appears to be the second case of composite tumor of the gallbladder.

Absence of a mutation of the p21/WAF1 gene in human lung and pancreatic cancers

The expression of a negative regulator of the cell cycle, p21WAF1 protein, is trans‐activated hy wild‐type p53, but not by the mutant protein. Therefore, mutations of the p53 and WAF1 genes may be complementary. We examined DNAs from 70 human primary lung (63 of NSCLC and 7 of SCLC) and 24 pancreatic cancers (19 primary cancers and 5 cell lines) for mutations of the WAF1 gene. No mutations were detected in any samples examined, regardless of the mutational state of the p53 gene. The results suggested that aberrations of the coding sequence of the WAF1 gene are not associated with carcinogenesis in lung and pancreatic cancers.

Leiomyosarcoma of the pancreas. Report of a case and review of the literature.

A case of leiomyosarcoma of the pancreas, occurring in a 44-year-old male, is reported. With a preoperative diagnosis of cystadenocarcinoma, the patient underwent surgical resection of a cystic tumor in the head of the pancreas. There were no metastases noted at the time. The resected specimen was diagnosed histologically as a smooth muscle tumor originating from the pancreas. It was seemingly benign on the basis of the mitotic counts and the degree of cellular atypism. However, the tumor proved to be malignant; the patient died with metastases to the liver. The tumor at autopsy also had few mitoses (0-1/10 hpf). The previously reported cases were reviewed and the limitations of histological diagnosis in assessing malignant potential of smooth muscle tumors are discussed.

Association of cumulative allelic losses with tumor aggressiveness in hepatocellular carcinoma.

BACKGROUND/AIMSnLoss of heterozygosity on various chromosomal arms has been reported in hepatocellular carcinoma and a multistep accumulation of genetic alteration has become accepted as the mechanism underlying progression of the disease. Although cumulative genetic alterations may imply more malignant tumors with poorer prognosis, the assumption requires further investigation.nnnMETHODSnPresence of loss of heterozygosity was analyzed by microsatellite markers at 13 loci on six chromosomal arms in 56 hepatocellular carcinomas. Association with cumulative allelic losses and prognosis of the patient following curative resection was studied.nnnRESULTSnFrequency of allelic losses at each chromosomal arm was 31% on 1p, 20.6% on 4q, 17.5% on 8p, 17.5% on 13q, 25.5% on 16q and 17.4% on 17p. Thirty-three tumors (59%) presented loss of heterozygosity. Tumors with more allelic losses were significantly more likely to be un-infected by hepatitis C virus, and to be histologically poorly differentiated, to have higher alpha-feto protein value, to be advanced in T classification and in tumor stage. Patients with more than one loss of heterozygosity revealed poorer 3-year disease-free survival than those with one or no (p=0.0004). A multivariate Cox model analysis revealed cumulative loss of heterozygosity as an independent and influential factor for disease recurrence (relative risk, 2.66; 95% confidence interval, 1.23-5.75; p=0.013), followed by tumor stage.nnnCONCLUSIONSnCumulative loss of heterozygosity reflects the multistep genetic mechanism of progression of hepatocellular carcinoma. The study confirms the potential significance of genetic analysis in the management of the disease.