New Method for Identifying Tumor-Promoting Genes in Breast Cancer

Understanding Oncogenes and Breast Cancer Subtypes

Researchers have introduced an innovative technique to identify tumor-promoting genes, which has been utilized to uncover potential drug targets for breast cancer treatment. Oncogenes are specific genes whose expression facilitates tumor development. The identification of oncogenes linked to breast cancer has significantly enhanced our understanding of the disease, leading to the classification of breast cancer into five subtypes based on their oncogene expression profiles.

This classification is clinically important as it aids in patient classification, particularly since each subtype exhibits distinct risk factors, prognosis indicators, and varying responsiveness to treatment options. Such categorization is essential for determining appropriate treatment strategies and for patient inclusion in clinical trials.

The Challenge of Treatment Resistance

Despite advancements in understanding breast cancer—one of the most well-characterized cancers—many patients either do not respond to treatments or develop resistance. Researchers believe this is partly due to the incomplete understanding of tumor type diversity. There have been extensive efforts to refine methods for analyzing cancer patients’ genomic data to identify elusive oncogenes, which could serve as new drug targets and improve tumor classification.

Utilizing Genome-Wide Gene Expression Data

A Novel Statistical Approach

In a recent publication in the British Journal of Cancer, a collaborative study by American and Australian researchers introduces a new statistical method for identifying oncogenes. This method leverages recently available genome-wide gene expression data from tumors and adjacent healthy tissues of hundreds of patients.

Associate Professor Jess Mar, one of the study’s authors, explained the challenge this method addresses: “If an oncogene is over-active in one group of patients but inactive in another group, that’s statistically harder to see using the tools that we had available. If you only look at the average activity of a gene across the two groups, you’d never see the high activity in the first group.”

Identifying Potential Oncogenes

The effectiveness of this new method, named Oncomix, was evaluated using data from The Cancer Genome Atlas, which included gene expression data from 110 Caucasian women diagnosed with breast cancer. Remarkably, the method identified five new potential oncogenes. Notably, one gene, CBX2, which regulates cell proliferation, showed minimal expression in healthy tissues but significant over-expression in aggressive tumors.

When researchers inhibited CBX2 in a breast cancer cell line, they observed a slowdown in cell growth, suggesting that CBX2 may contribute to tumor progression. The dual characteristics of CBX2—its ability to promote cancer cell growth and its low expression in healthy tissues—render it an appealing candidate for the development of novel drugs targeting aggressive breast cancer types.

Conclusions and Future Implications

The findings from this study are promising, presenting a new methodology for uncovering “hard-to-find” oncogenes applicable to any cancer type with available gene expression data. Furthermore, the identification of CBX2 as a potential oncogene candidate in aggressive breast carcinoma highlights its potential as a new therapeutic target for breast cancer treatment.

Written by Maria Isabel Acosta Lopez, PhD, Medical Writer.

References

Piqué, D. G., Montagna, C., Greally, J. M., & Mar, J. C. (2019). A novel approach to modelling transcriptional heterogeneity identifies the oncogene candidate CBX2 in invasive breast carcinoma. British Journal of Cancer.
University of Queensland. (2019, March 8). New gene hunt reveals potential breast cancer treatment target. EurekAlert!. Retrieved March 12, 2019 from https://www.eurekalert.org/pub_releases/2019-03/uoq-ngh030819.php
Clinical implications of the intrinsic molecular subtypes of breast cancer. (2015). Clinical implications of the intrinsic molecular subtypes of breast cancer., 24 Suppl 2, S26–35. http://doi.org/10.1016/j.breast.2015.07.008