The tumor suppressor gene MEN1 and several oncogenes including CCND1/cyclin D1/PRAD1 map to chromosome 11q13. However, molecular and cytogenetic analysis suggests the presence of a second tumor suppressor locus at this chromosome region. We have identified a novel gene from chromosome 11q13, which encodes a protein of 126 amino acids sharing an overall 57% identity with the p12DOC-1 protein encoded by the DOC-1 gene, the human homolog of hamster putative tumor suppressor doc-1 (deleted in oral cancer-1). We therefore designated the novel gene as DOC-1R for DOC-1-related. The cytogenetic location was con-firmed by chromosome fluorescent in situ hybridization. Northern blot analysis indicated that it was expressed in all the tissues examined. DOC-1R protein showed heterogeneous subcellular localization. RTPCR-SSCP analysis failed to detect deleterious mutations of the DOC-1R transcript in four premalignant oral keratinocyte lines and 20 different cancer cell lines from tumor types which frequently harbor LOH at chromosome 11q13.

We prospectively screened (through chart review) 913 consecutive patients who were seen at the Massachusetts General Hospital (MGH) Melanoma Clinic over a 6-month period (December 1997 to August 1998) and identified 519 patients with invasive melanomas. TheMGHMelanoma Clinic is a referral-based clinic for patients with a history of melanomaand high-risk individuals with a history of atypical moles or a family history of melanoma. We identified 172 patients whowere or had been diagnosed as having an invasive or metastatic melanoma before they were 40 years old. The diagnoses did not have to have been rendered during the ascertainment period; the average interval between melanoma diagnosis and the study visit was 5.9 years (range, 0 [time at diagnosis] to 30 years). Only diagnoses that were histologically confirmed by a member of the MGH Dermatopathology Unit were included. Patients with a diagnosis of melanoma in situ were excluded, given the occasional ambiguity between melanoma in situ and severely dysplastic nevus. At the time of the clinic visit, each of the 172 patients was provided with a detailed letter describing the study. Those patients expressing interest then underwent an extended discussion regarding the study content and risks. A total of 49 patients (28%) consented to the study and, in accordance with a protocol approved by the Dana Farber Cancer Institute and theMGHInstitutional Review Board, donated 20mLof blood for genetic analysis. The blood samples were coded, and the confidentiality of the patients was maintained. The results were not available to the patients. Medical and family histories and demographic details of participants were recorded through chart review and direct interview. All 49 patients were white and were unrelated to one another. Forty-three blood specimens from normal, healthy blood donors at heMGHblood bank were used for analysis of the polymorphism.

Tumor invasion and metastasis are the most common causes of death in gastric carcinoma. Human heparanase influences tumor invasiveness and angiogenesis. Analysis of its expression in gastric carcinoma has been hindered by our inability to procure pure cancer cells from heterogeneous tissue. In the present study, we analyzed heparanase expression in human primary and metastatic gastric carcinoma cells as well as in paired normal gastric epithelial cells by laser capture microdissection coupled with reverse transcriptionpolymerase chain reaction (RT-PCR). Tumor tissues, metastatic lymph nodes, and apparently uninvolved normal gastric tissues were collected from 30 patients who had undergone gastrectomy with radical lymph node dissection for gastric carcinoma without preoperative treatment. Bulk tissues and laser capture microdissected cell groups were separately subjected to RT-PCR analysis with heparanase-specific primers. For bulk tissues, heparanase-specific transcripts were detectable in all primary tumor tissues, metastatic lymph nodes, and almost all matching normal tissues. RT-PCR analysis after laser capture microdissection showed no detectable heparanase expression in matching normal epithelial cell groups. Of the laser capture microdissected primary gastric carcinoma cells, 47% (14/30) were heparanase positive. Expression was closely associated with greater tumor invasiveness, including Borrmann gross type and depth of wall infiltration. For metastatic cell groups dissected from lymph nodes, 95% showed clear heparanase expression. urthermore, the extent of lymphatic spread was directly correlated to heparanase expression at the primary site. In conclusion, laser capture microdissection coupled with RT-PCR is a reliable approach for molecular analysis of heparanase expression in gastric carcinoma. Heparanase may facilitate invasion and metastasis of gastric carcinoma cells.

Large scale gene expression pro

Both inactivation of the tumor suppressor gene, PTEN/MMAC1, and oncogenic activation of RAS have been described in human cutaneous melanoma. In mice, activation of a RAS-containing pathway is a necessary step in the pathogenesis of murine melanomas. Because PTEN negatively regulates on the downstream effects of phosphatidylinositol-3-kinase (PI3-K), we hypothesized that the loss of PTEN/MMAC1 and the activation of RAS may be largely equivalent because RAS is a known positive upstream regulator of PI3-K. We expanded our previous survey of PTEN/MMAC1 mutations and analyzed the RAS status of 53 cutaneous melanoma cell lines, 18 glioma cell lines, and 17 uncultured cutaneous melanoma metastasis. Overall, 51% of the cell lines had alterations in either PTEN/MMAC1 or RAS. We found 16 cell lines (30%) with alterations in PTEN/MMAC1 and 11 cell lines (21%) with activating NRAS mutations; only 1 cell line had concurrent alterations in both genes. Moreover, glioma cell lines with a high frequency of PTEN/MMAC1 inactivation had no identifiable RAS alterations. Ectopic expression of PTEN in several cutaneous melanoma cell lines suppressed colony formation irrespective of PTEN/MMAC1 status; urthermore, PTEN expression in cell lines carrying activated RAS also suppressed colony formation. The relative reciprocity of PTEN/MMAC1 abrogation and NRAS activation suggests that the two genetic changes, in a subset of cutaneous melanomas, are functionally overlapping.