Many patients with cutaneous T-cell lymphoma contract Staphylococcus aureus infections in the skin. In a new study, researchers have shown that aggressive treatment with antibiotics for patients with these infections not only inhibits the staphylococcal bacteria—but also the cancer cells. In the study, the number of cancer cells was reduced and the cancer was significantly diminished for up to 8 months in patients with severe skin inflammation. These findings were published by Lindahl et al in Blood.
During a staphylococcal infection, healthy immune cells produce cytokines, which cancer cells latch on to and accelerate their own growth. The research results show that antibiotic treatment may slow down this process.
“When we inhibit the staphylococcal bacteria with antibiotics, we simultaneously remove the activation of the immune cells. This means that they do not produce as many cytokines, and therefore the cancer cells cannot get the extra ‘fuel.’ As a result, the cancer cells are inhibited from growing as fast as they did during the bacterial attack. This finding is groundbreaking, as it is the first time ever that we see this connection between bacteria and cancer cells in patients,” said study author Niels Ødum, MD, DMSci, of the LEO Foundation Skin Immunology Research Center.
In the prospective study, the researchers studied the effect of transient antibiotic treatment in eight patients with advanced-stage cutaneous T-cell lymphoma. All patients experienced a significant decrease in clinical symptoms after antibiotic treatment—in some patients, clinical improvements lasted for 8 months or more. In six patients, a malignant T-cell clone could be identified in lesional skin, and a decrease in malignant T cells was observed after treatment with antibiotics (and no other changes to their treatment regimen). Aggressive antibiotic therapy was also associated with decreased expression of IL-2 high-affinity receptors, STAT3 signaling, and cell proliferation in lesional skin.
“It has previously been seen that antibiotics have had some kind of positive effect on some of these patients, but it has never been studied what it actually does to the cancer itself. Our finding shows that it may actually be a good idea to give this treatment to patients with staphylococci on the skin, because it inhibits the cancer and at the same time possibly reduces the risk of new infections,” said Dr. Ødum.
It is still difficult to say whether the new knowledge may be transferred to other types of cancer. For researchers, the next step is to initially look more closely at the link between cancer and bacteria.
“We do not know if this finding is only valid for lymphoma. We see it particularly in this type of cancer because it is a cancer within the immune system. The cancer cells already ‘understand’ the signals that the immune cells send out. When the immune cells are put to work, so are the cancer cells. At any rate, it is very interesting and relevant to take a closer look at the interaction between bacteria and cancer, which we see here,” said Dr. Ødum.
“The next step will be the development of new treatments that only target the ‘bad’ bacteria, without harming the ‘good’ bacteria, which protects the skin.”
Disclosure: For full disclosures of the study authors, visit bloodjournal.org.
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