Categorized | Feature, Prostate Treatment

Gene Test Effectively Predicts Presence of nearby Prostate Cancer

Data from a large group of tissue samples showed that gene expression in prostate stroma predicted the presence of nearby cancer with 97% overall accuracy.  Stroma adjacent to or near prostate tumors expressed genes significantly differently from normal stroma.

In a recent issue of Cancer Research, it was reported that the correlation between stromal gene expression and cancer increased with proximity to cancer.  The 144-gene panel had 98% sensitivity and 88% specificity for predicting the presence of cancer, whereas, a randomly selected 100-gene panel had no predictive value.  If replicated in additional studies, the gene test has multiple therapeutic implications.

The research team compared gene expression profiles in 13 prostate biopsy specimens containing stroma near tumor and in 15 biopsy specimens from men without prostate cancer and identified 3,800 significant changes in expression.

The authors developed a 114-gene stroma-specific classifier for nearby tumor after filtering for age-related genes and for genes known to be expressed at detectable levels in tumors.  They tested the classifier in 364 prostate specimens, consisting of 243 tumor-bearing samples and 121 normal specimens.  These 364 specimens included samples from normal prostate biopsies, normal prostate tissue obtained from autopsies, stroma remote to tumor, and stroma from within a few millimeters of tumor.  The gene panel correctly identified all but two of the 243 tumor-containing specimens. Analysis of the two misclassifications suggested the tissue might not have come from patients with prostate cancer.

The research team also compared expression patterns in stromal tissue near and far from the tumor and found a gradient of classification frequency values of 98%, 75%, and 36% for stromal samples adjacent to, close to, and remote (>15 mm) from the tumor.

These findings suggest several practical applications of the gene test, such as assessment of suspicious initial biopsies and possibly therapeutic targeting of stromal expression changes indicating the presence of tumor while leaving normal stroma relatively untouched.

Some of the authors of the gene expression study disclosed relationships with Proveri, a company involved in translational research related to the study.

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February 2012
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