Sir,
We thank Khan et al (2011) for their valuable and insightful comments on our study (Mazouni et al, 2011) expounded in their Letter to the Editor (Khan et al, 2011).
In our initial publication, we demonstrated the presence of the Epstein–Barr virus (EBV) in malignant breast tumours, which is consistent with findings in previous international publications (Fina et al, 2001). In the paper, they are referring to, we observed the same positivity rate as previously noted using a more precise PCR technology. Khan et al (2011) suggest that the positivity findings in BC specimens may have been biased by EBV-infected lymphocytes. As mentioned in our paper, our aim was to ascertain the presence of EBV in epithelial cells by isolating these cells using laser microdissection capture (LMC) (Mazouni et al, 2011). A large amount of tissue (100 mg) was used to extract DNA from our specimens and this might explain why EBV was detected at a higher frequency than in other studies. In their study, Khan et al (2010) did not perform LMC to ensure the validity of epithelial cell positivity.
Besides, another valuable criticism leveled by Khan et al (2010) concerns the controversial association between EBV and BC. Other retroviruses have been reported to induce BC. In a previous report, Berebbi et al (1990) induced the development of BC in an experimental model by modulating the presence of the polyoma virus during the development of the mammary gland . Moreover, the relationship between EBV and BC has been suggested in an epidemiological study (Yasui et al, 2001).
The aggressive profile of EBV-positive BC that we observed has previously been reported in other series (Bonnet et al, 1999; Murray et al, 2003). Moreover, the differentiation markers evaluated in the breast specimens are associated with the epithelial component.
Finally, we agree that EBV is a ubiquitous infection that makes the physiopathology of BC development difficult to explain. There is still a long road ahead in the field of virus-related cancer before we will be able to formally assess their role and propose prevention.
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