Genetics Lead the Way to Targeted TNBC Treatment: 17q25.3

The q25.3 region of chromosome 17 may be another genetic marker that defines subtypes of triple-negative breast cancer and, therefore, could lead to the golden grail: targeted treatment, especially for those forms of TNBC linked to the BRCA1 mutation.  In research published in the journal Breast Cancer Research, 17q25.3 was detected in 86 percent of the mutated TNBC tumors.

This is significant because, as the researchers note, the BRCA1 mutation is closely linked to TNBC, with  as many as  90 percent of tumors with the mutation being triple negative.  This does not mean, however, that all TNBC tumors have the BRCA1 mutation.  In fact, only 10 to 20 percent of all TNBC tumors have the BRCA1 mutation.  I explain this link in my book on TNBC.

Identifying patients with the BRCA1 mutation will ultimately help select patients who could benefit from  selective treatments 17q25.3.   First, though, we need those treatments.  Baby steps, friends.  But at least they are steps.

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For more details on triple-negative breast cancer, check out my book, Surviving Triple-Negative Breast Cancer.

Genetic Details of Triple-Negative Breast Cancer

Beyond its most basic definition—negative for receptors for estrogen, progesterone and Her2/neu—triple-negative breast cancer has unique genetic characteristics.  Research published April 1, 2013 in the journal Cancer Research has outlined some of TNBC’s genetic associations.  Researchers keep getting closer to finding what makes TNBC tick.  Once they know that, they can target it.  Put a big red bull’s eye on its nasty old back. 

Some details of the research:

• TNBC is more likely to be associated with TOX3, ESR1, RAD51L1, TERT, 19p13.1, 20q11, MDM4, 2p24.1, and FTO.

• 70 percent of those with the BRCA1 mutation who get breast cancer get TNBC.

• 16  to 23 percent of those with the BRCA2 mutation who get breast cancer get TNBC.

• Variations in the 19p13.1 locus and the MDM4 locus have been associated with TNBC, but not other forms of breast cancer, meaning that these are TNBC-specific.

• TNBC accounts for 12 to 24 percent of all breast cancers.