An extensive research conducted by Canadian and British laboratories, which has been based on crossing genetic information and clinical data of 1,000 women treated for breast cancer, to observe their response to therapies and the evolution of the disease in these patients -with a follow-up of up to ten years- has allowed to elaborate a new classification of breast cancer, establishing 10 different subtypes of tumors.

So far, only four different types of breast cancer have been identified - which were based on the presence or absence of hormone receptors, and in the presence of the HER2 protein - and this discovery will contribute to the development of personalized therapies depending on the type of tumor present each patient, in addition to avoiding chemotherapy after surgery when possible, and also depending on the variety of cancer diagnosed.

The discovery will contribute to the development of personalized therapies depending on the type of tumor presented by each patient, in addition to avoiding chemotherapy after surgery when possible.

The study, funded by the non-profit organization 'Cancer Research' and published in 'Nature', has also determined that generally each of the groups would cover 10% of all cases of breast cancer that are diagnosed annually in the world - amounting to 1.4 million cases-, except for subgroup 2, which is the worst prognosis but also the least frequent, and subgroup 4 - which has a good prognosis and affects 15% of patients diagnosed with this disease.

Researchers at Cancer Research have warned that it should still take between three and five years for this new classification of tumors to be used in clinical practice, thereby benefiting patients, since the information obtained in the study is first available. to contrast in the clinical trials that are carried out from now on, although they trust that it will be useful to develop new medicines that act against the new genes whose implication in the cancer have discovered.

Types of tumors

  • IntClust 3 and 4, considered of good prognosis, which include tumors characterized by low genomic instability, which have both positive and negative hormone receptors.
  • IntClust2, of poor prognosis, and with positive estrogen receptors. These tumors have some genes that were already known for their relationship with breast and ovarian tumors.
  • IntClust 1, 6, 7, 8 and 9, it is an intermediate group in which tumors with positive hormone receptors and basal carcinomas predominate.
  • A subgroup of tumors that has a poor prognosis during the first five years after diagnosis, but if the patient exceeds this period, there is a good chance of being cured.
  • A subgroup that was already known and that represented ERB2 positive tumors, which are currently treated with the drug trastuzumab, very effective against this type of tumors that, before this therapy was available had a worse prognosis.

Understanding Breast Cancer (November 2019).