Cytokine levels in breast cancer are highly dependent on cytomegalovirus (CMV) status

Purpose: Breast cancer accounts for 30% of all female cancers in the US. Cytomegalovirus (CMV), a herpesvirus that establishes lifelong infection, may play a role in breast cancer. CMV is not oncogenic, yet viral DNA and proteins have been detected in breast tumors, indicating possible contribution to tumor development. CMV encodes cmvIL-10, a homolog of human cellular IL-10 (cIL-10) with potent immunosuppressive activities. We investigated the relationship between CMV infection, cytokines, and breast cancer. Methods: We evaluated CMV serostatus and cytokine levels in plasma of women with benign breast disease (n = 38), in situ carcinoma (n = 41), invasive carcinoma, no lymph node involvement (Inv/LN−; n = 41), and invasive with lymph node involvement (Inv/LN+; n = 37). Results: Fifty percent of the patient samples (n = 79) were CMV seropositive. There was no correlation between CMV status and diagnosis (p = 0.75). For CMV+ patients, there was a trend toward higher CMV IgG levels in invasive disease (p = 0.172). CmvIL-10 levels were higher in CMV+ in situ patients compared to the Inv/LN− and Inv/LN+ groups (p = 0.020). Similarly, cIL-10 levels were higher in CMV+ in situ patients compared to the Inv/LN− and Inv/LN+ groups (p = 0.043). The results were quite different in CMV− patients where cIL-10 levels were highest in Inv/LN− compared to benign, in situ, or Inv/LN+ (p = 0.019). African American patients were significantly associated with CMV+ status (p = 0.001) and had lower cmvIL-10 levels than Caucasian patients (p = 0.046). Conclusion: No association was observed between CMV IgG and diagnosis, but CMV infection influences cytokine production and contributes to altered cytokine profiles in breast cancer.