Medical Mogul: Cure or Correlation?

Breast Cancer Hits Headlines

According to the latest news, the BBC reports that scientists investigating the levels of the RUNX1 protein, typically expressed in patients suffering from leukaemia, is also related to more deadly triple negative breast cancer. The BBC article suggests that this could be a cure if the gene was inhibited: I looked deeper into this headline.

The Research

Currently Oestrogen positive subtypes of breast cancer can be effectively treated using hormone therapy, whereas HER2- positive cancers can be tackled through use of the Herceptin drug. However both of these treatments do not have an effect on the breast cancer subgroup, triple negative tumours. This means that these tumours have to be treated using chemotherapy (generally using a combined drug) or through use of surgery or radiotherapy which may use chemotherapy as an adjuvant treatment. However the success rate of treating triple negative tumours with combined drugs has increased and is now capable of being able to help target patients with very sensitive tumours. As a result, this decreases the probability that a new treatment may be more effective than this due to the level of research and clinical development already associated with chemotherapy. Thus this may mean that any new treatment may require extensive research in order to allow it to be used more efficiently and hence therefore act as an improvement.

Nevertheless this may not be a significant issue as the rate of genetic treatments for cancer types and genetic tests to help with prognosis, has increased in the last decade and have helped to identify and remove 70% of all tumours. Consequently, considering the rate of advancement in this sector, a genetic approach to treating triple negative breast cancer may be more significant and influential in the long-term hence increasing the versatility of medicine in order to tackle a wider range of tumours and hence therefore offer more effective treatments.

The actual research suggests that, in a sample of 438 patients suffering from triple negative cancer, those with the RUNX1 protein being expressed were four times more likely to die. This is important as it demonstrates that over a large sample size the results were consistent. This implies that the results were not affected by chance and so therefore this suggests that the results are more representative and hence are reliable. This increases the credibility of the results because it increases my trust in the results. Nevertheless, the PLOS one journal, where the data was initially published, only regarded the increased probability of death occurring when the RUNX1 gene was expressed. This means that there is little data analysing other factors associated with breast cancer (e.g. whether the cancer was likely to return, whether it affected the success of chemotherapy, whether those who survived triple negative cancer when the RUNX1 protein was present had more severe symptoms), this limits the validity of the data as it doesn’t necessarily show that the presence of the RUNX1 gene can produce a more “dangerous” cancer; “dangerous” is subjective; what is “danger”?

In order to assess the significance of this discovery, we must also consider “what was the original risk?” According to www.breastcancer.org, women with triple negative breast cancer have a five year survival rate of 77%. This means that with the RUNX1 gene only 19.25% of women survive after 5 years. Thus, this could be argued as dangerous and so the significance of this discovery is increased. However, this website also suggested that after the five year period the risk is less. Thus the long-term risk to women is less. Nevertheless, this risk is still high and so this supports the importance of the research as it offers a better potential to save life.

In contrast, RUNX1 expression did not affect the result of “oestrogen receptor (ER)- positive or HER2-positive disease” in a multivariate test (a test where many variables can change). Thus this implies that realistically, when considering the variations and differences in chemical concentration in the body, different variables will change and so this means that the success of targeting the RUNX1 gene may be limited if it is only successful in a univariate test. In addition, this data only shows a correlation and does not suggest a causal mechanism how RUNX1 could cause more deadly cancer types. This was discussed by Dr Karen Blyth who stated “first we need to prove this gene is causative to the cancer”. Thus this implies that the data is very much uncertain and only shows a potential link. This reduces the viability of the research being used in treatment.

Adding to this, the gene has a complex role and (as stated by Wikipedia) “regulates the differentiation (change) of stem cells into blood cells”. Hence, arguably, by inhibiting the RUNX1 gene, which is a likely application if treatment was going to use this research, it may cause more serious side effects and so this may be more important and dangerous than the breast cancer in extreme cases; particularly considering that most women develop breast cancer between the ages of 70 and 80 where they may be infirm and susceptible to complications.

Even so research is particularly valuable in order to encourage further research which is important to this case as the PLOS one journal is an international, peer-review journal and so this means that it has been checked to ensure that the results are repeatable and that the interpretation of these results was correct. This means that errors and mistakes have been eliminated, increasing reliability. Adding to this, the area of research is particularly large considering that breast cancer is the “third most common cause of cancer death in the UK, accountable for more than 11,000 deaths in 2011 alone (www.cancerresearchuk.org) and an estimated 39,620 female deaths in the USA in 2013 (www.cancer.gov)”. In addition, 15-20% of those with breast cancer suffer from triple negative cancer. This means that more than 5943 people die from triple negative cancer in the USA (15% of 39620 though the death rate is probably higher than this as triple negative cancer has a higher mortality rate than other cancers).

My Verdict

To conclude, this is an exciting study as it shows the potential for genetic treatments or, at least, genetic prognosis by identifying the levels of RUNX1 protein in the body. Therefore this means that the potential for research is greater and hence increases the possibility that this will increase survival rates and hence continue the trend expressed in the graph. However, we must also consider other research, such as the scientists at University College London who believe that a blood test for breast cancer could be developed following research. Consequently, we must be careful not to exclude this area of research over a more ambitious potential ‘cure’ as both are equally as valuable. Despite these exciting developments though, the headlines can be misleading as “correlation” does not denote “cause”.