Core Needle Biopsy Gives an Accurate Picture of Gene Expression in Whole Tumor

Behind the Cancer Headlines®

August 22, 2006

The gene expression profile detected in the core needle biopsy of a breast tumor is representative of gene expression in the whole tumor. A study published in the journal Breast Cancer Research confirms the reliability of core needle biopsy as a tool in breast cancer diagnosis and prognosis.

The study also shows that the gene expression profile of a core needle biopsy might be more accurate than the profile of a surgical sample taken from the same tumor, after the biopsy was carried out. According to the study results, the biopsy procedure seems to trigger the expression of genes involved in wound healing as well as tumor invasion and metastasis, thus modifying the gene expression profile of subsequent surgical samples.

Rosanna Zanetti-Dällenbach from the Women's University Hospital in Basel, Switzerland and colleagues from Stiftung Tumorbank, OncoScore AG and University Hospital in Basel, analyzed the gene expression profile of core needle biopsies taken from 22 women diagnosed with breast cancer. For each woman, they compared the biopsy expression profile with the expression profile of a surgical sample taken from the tumor subsequently to the core needle biopsy. Zanetti-Dällenbach et al. quantified the expression of 60 genes known to be involved in breast tumor development using a technique called reverse polymerase chain reaction (PCR). The researchers also analyzed the gene expression profiles of surgical samples taken from the breast tumors of 317 patients who did not undergo a core needle biopsy.

The results of their study show that the gene expression levels of the core biopsy and the surgical sample are identical for most women. But the authors found that the expression of four specific genes is significantly increased in the surgical samples compared to the core needle biopsies. In the group of women who did not get a core needle biopsy, however, the expression of these four genes was not increased. These four genes are involved in inflammation and wound repair as well as tumor invasion and metastasis.

The authors conclude that their expression must therefore be modified by the core needle biopsy procedure itself. They warn that care should be taken when interpreting the gene expression profile of a surgical sample carried out following a core biopsy. Although the tumor's aggressiveness has not changed, the modified profile in surgical samples obtained after core needle biopsy might influence data interpretation with respect to prediction of risk assessment and treatment response. The core needle biopsy sample may give a cleaner, more accurate and more representative profile of the levels of gene expression in the tumor.

SOURCE:

Breast Cancer Research, online edition, August 18, 2006