Cytomegalovirus and systemic inflammation at time of surgery is associated with worse outcomes in serous ovarian cancer

Quantification of low-level human cytomegalovirus and Epstein-Barr virus DNAemia by digital PCR

BACKGROUND

Digital PCR (dPCR) can quantify cell-free viral DNA (DNAemia), a biomarker of active viral infection. To accelerate epidemiologic investigation into low-level viral reactivation in chronic disease, we have evaluated the performance of dPCR to detect cytomegalovirus (CMV) and Epstein-Barr virus (EBV) DNAemia across platforms and blood matrices.

METHODS

The droplet-based (BioRad) dPCR platform performance was compared to chip-based (BioMark), and assay validation followed dMIQE guidelines. CMV and EBV DNA reference materials were spiked into known negative plasma and serum samples. In addition, two independent cohorts of ovarian cancer patients were evaluated for viral DNAemia (n = 65 serum and 79 plasma samples).

RESULTS

The limit of quantification (LOQ) was at or slightly above 100 copies/mL for both instruments: 105-135 copies/mL for droplet-based detection and 100 copies/mL for chip-based detection. DNAemia in serum had a slightly lower LOQ (105-110 copies/mL) compared to plasma (LOQ; 115-135 copies/mL). The variation (CV) coefficients for each assay and machine were less than 5 %. In patient samples, CVs ranged from 4.5 - 7.4 % and were similar for cell-free DNA derived from serum or plasma. There was good correlation between DNAemia measurements in patient samples across dPCR platforms (r > 0.90 for each assay and matrix).

CONCLUSION

dPCR can quantify low-level herpes virus DNAemia with CVs below 8 %. Our results indicate that using serum-derived cell-free DNA and droplet-based dPCR is optimal for quantitating low-level viral DNAemia; however, plasma and chip-based approaches are acceptable alternatives and suitable for epidemiologic investigation.

Association between cytomegalovirus infection and cancer‑related mortality in the US adults

PURPOSE

In a nationwide cohort of US adults, an exploration of the association between cytomegalovirus (CMV) infection and cancer‑related mortality was conducted.

MATERIALS AND METHODS

We acquired data from the National Health and Nutrition Examination Survey III (1988-1994), including 11,138 individuals who were aged 18-90 years at enrollment and underwent CMV serology assessments. CMV infection was determined by CMV antibody testing. Cancer‑related mortality status was ascertained until December 2019 utilizing the National Death Index linkage data and determined by neoplasms. The Cox proportional hazard model was applied to estimate the potential association between CMV infection and the risk of cancer-related mortality.

RESULTS

During a median follow-up of 26.1 years, 1514 cancer‑related deaths were identified in the study cohort. After adjusting for age, sex, and ethnicity, CMV infection was associated with a higher hazard of cancer‑related mortality (hazard ratio [HR]: 1.39, 95 % CI: 1.13, 1.70). Further adjustments for body mass index, family income, and smoking status slightly attenuated the magnitude of the association (HR: 1.24, 95 % CI: 1.00, 1.53). However, no significant interaction was observed among gender by subgroup analysis.

CONCLUSIONS

CMV infection might be an independent risk factor for cancer‑related mortality among US adults. Future studies could focus on the mechanisms through which CMV infection influences mortality induced by neoplasms and develop targeted interventions to reduce the risk.

Prevalence of active cytomegalovirus infection at diagnosis of ovarian cancer and during chemotherapy and subsequent changes in cognitive functioning

PURPOSE

One of the most frequently reported effects of cancer and its treatments is cancer-related cognitive impairment (CRCI). Viral infections may affect inflammation and immune function and therefore may influence patient symptoms, including CRCI. The goal of this study was to describe the prevalence of cytomegalovirus (CMV) infections at diagnosis, during, and after chemotherapy in individuals with ovarian cancer and explore CMV infection at diagnosis with cancer-related cognitive impairment (CRCI) following chemotherapy.

METHODS

We recruited adults newly diagnosed with ovarian, primary peritoneal or fallopian tube cancer at a single academic cancer center into two prospective studies. In Study 1 (N = 71), participants provided blood samples at diagnosis. In Study 2 (N = 18), participants provided blood samples and completed symptom surveys before, during and after front-line adjuvant chemotherapy. Serum CMV DNA levels were assessed using digital PCR; >100 copies/mL of serum was considered positive for active CMV infection (CMV+). CRCI was measured using the Functional Assessment of Cancer Therapy - Cognitive Function (FACT-Cog) questionnaire. Changes in FACT-Cog scores were compared by CMV status at diagnosis using t-tests at each time point.

RESULTS

At diagnosis, 29.2% were CMV+ (28.2% in Study 1, 33.3% in Study 2). Following three cycles of chemotherapy (Study 2), CMV positivity rose to 60.0% and then back down to 31.3% after chemotherapy. We observed significant differences in CRCI following chemotherapy by CMV status at diagnosis.

CONCLUSION

Our data suggest that active CMV infection is common among patients undergoing treatment for ovarian cancer and may contribute to symptoms of CRCI.