The systemic delivery of an oncolytic adenovirus expressing decorin inhibits bone metastasis in a mouse model of human prostate cancer.

In an effort to develop a new therapy for prostate cancer (PCa) bone metastases, we have created Ad.dcn, a recombinant oncolytic adenovirus carrying the human decorin gene. Infection of PC-3 and DU-145, the human prostate tumor cells, with Ad.dcn or a non-replicating adenovirus Ad(E1-).dcn resulted in decorin expression; Ad.dcn produced high viral titers and cytotoxicity in human prostate tumor cells. Adenoviral-mediated decorin expression inhibited Met, the Wnt/ß-catenin signaling axis, vascular endothelial growth factor A, reduced mitochondrial DNA levels and inhibited tumor cell migration. To examine the antitumor response of Ad.dcn, PC-3-luc cells were inoculated in the left heart ventricle to establish bone metastases in nude mice. Ad.dcn, in conjunction with control replicating and non-replicating vectors were injected via tail vein. The real-time monitoring of mice, once a week, by bioluminescence imaging and X-ray radiography showed that Ad.dcn produced significant inhibition of skeletal metastases. Analyses of the mice at the terminal time point indicated a significant reduction in the tumor burden, osteoclast number, serum tartrate-resistant acid phosphatase 5b levels, osteocalcin levels, hypercalcemia, inhibition of cancer cachexia and an increase in the animal survival. Based on these studies, we believe that Ad.dcn can be developed as a potential new therapy for PCa bone metastasis.

Molecular detection of Mycobacterium tuberculosis: impact on patient care.

BACKGROUND: Nucleic acid amplification technologies such as PCR are revolutionizing the detection of infectious pathogens such as tuberculosis (TB). Amplification technology offers the potential for the diagnosis of TB in a few hours with a high degree of sensitivity and specificity. However, molecular assays neither replace nor reduce the need for conventional smear and culture, speciation, and antibiotic sensitivity assays. METHODS: We undertook prospective studies of sputum samples to assess the performance of two PCR-based assays for the detection of TB as well as the impact of more rapid availability of test results on patient care. RESULTS: The sensitivity of both the in-house and Amplicor PCR assays was 100% for smear-positive sputa. For smear-negative sputa (two sputum samples collected during the first 24 h of hospitalization), the sensitivity was 85% for our in-house PCR assay and 74% for the Roche PCR assay. Approximately 10% of the smear- and culture-negative sputa yielded positive PCR results; however, more than one-half of these were positive with both the in-house and Amplicor assays, suggesting the presence of TB DNA or organisms. Several of these came from patients whose other samples grew Mycobacterium tuberculosis during the same admission, and others came from patients who had previously treated TB. Overall, the specificities of the in-house and Amplicor PCR assays in smear-negative patients were 86% and 93%, respectively. CONCLUSIONS: Molecular detection of slow-growing pathogens such as M. tuberculosis have the potential to improve clinical care through a dramatic reduction in the time required for detection and may provide substantial savings in the overall cost of care of a patient compared with conventional smear, culture, and speciation alone, despite the fact that conventional assays must still be performed for speciation of nontuberculous mycobacteria and for full assessment of antibiotic sensitivity.

Tumor-infiltrating lymphocytes are a marker for microsatellite instability in colorectal carcinoma.

BACKGROUND: Cells with deficient DNA mismatch repair develop microsatellite instability. Extensive microsatellite instability (MSI-high) is characteristic of colorectal carcinomas in hereditary nonpolyposis colorectal carcinoma (HNPCC) and in 10-% 15% of sporadic colorectal carcinomas. Microsatellite instability-high colorectal carcinomas differ from others in important clinical and pathologic features. However, MSI typing is expensive and not widely available. Microsatellite instability type may be predicted by tumor-infiltrating lymphocytes (TILs), which can be evaluated with ordinary light microscopy. METHODS: The authors evaluated TILs as a pathology screen for MSI-high status in 138 colorectal carcinomas that had been evaluated for MSI in a variety of studies. This case series was systematically enriched with HNPCC and other MSI-high cases to allow accurate sensitivity and specificity estimation. Tumor-infiltrating lymphocytes were quantitated as TILs per 10 high-power microscopic fields by an observer blinded to MSI status. RESULTS: Of the 138 carcinomas studied, 67 (48.6%) were MSI-high, 22 (15.9%) were MSI-low, and 49 (35.5%) were MSI-stable. All 25 HNPCC colorectal carcinomas were MSI-high. Tumor-infiltrating lymphocytes counts ranged from 0 to 300, with a markedly skewed distribution (median, 11; mean, 36). Sensitivity and specificity for selected cut points of TIL count were computed. Using a TIL count of 5 as a cut point yields a sensitivity of 93% and specificity of 62%. In a population in which 12% were MSI-high, consideration of TIL could reduce the number of colorectal carcinomas referred for MSI testing by greater than one-half, and still 93% of the MSI-high carcinomas would be identified. CONCLUSIONS: The presence of MSI defines a subset of colorectal carcinomas with special molecular etiology and characteristic clinical, pathologic features, inclusive of increased survival. The authors conclude that quantification of TILs may provide a simple, single criterion for choosing which colorectal carcinomas are candidates for MSI testing.

Detection of breast cancer cells using immunomagnetic beads and reverse transcriptase polymerase chain reaction.

Molecular methods permit the detection of cells too few in number to be detected by light microscopy, immunohistochemistry, or flow cytometry (1-5). Numerous investigators are therefore developing sensitive and specific reverse transcriptase polymerase chain reaction (RT-PCR) assays for tumor cell detection. The detection of small numbers of tumor cells in blood, lymph node, and stem cell harvests may have a significant impact on our understanding of the spread of breast cancer, and eventually may impact the management of breast cancer patients as well.

Molecular detection of circulating prostate cancer cells.

Molecular methods have proven extremely useful for the detection of occult tumor cells and can yield valuable clinical information as well as a better understanding of the mechanisms of metastasis and relapse of cancer (1). In the case of many hematopoietic malignancies, the presence of a unique molecular marker such as a chromosomal translocation has made this task relatively straightforward. Carcinomas generally lack such markers, however. Certain oncogene mutations have been targeted, but the lack of consistent and specific markers has remained problematic.

Gastric stromal tumor.

Gastric stromal tumors display a bewildering array of immunohistological and ultrastructural features as well as variable biological behavior. These tumors are rare as compared with ones that arise from the gastric epithelium. Moreover, they have been the subjects of controversy because of their uncertain histogenesis. We report the pathological features of gastric stromal tumors we recently encountered in three patients.