Bone marrow plasma cell assessment before peripheral blood stem cell mobilization in patients with multiple myeloma undergoing autologous stem cell transplantation

Aberrant Plasma Cell Contamination of Peripheral Blood Stem Cell Autografts, Assessed by Next-Generation Flow Cytometry, Is a Negative Predictor for Deep Response Post Autologous Transplantation in Multiple Myeloma; A Prospective Study in 199 Patients

High-dose chemotherapy with autologous stem cell support (ASCT) is the standard of care for eligible newly diagnosed Multiple Myeloma (MM) patients. Stem cell graft contamination by aberrant plasma cells (APCs) has been considered a possible predictive marker of subsequent clinical outcome, but the limited reports to date present unclear conclusions. We prospectively estimated the frequency of graft contamination using highly sensitive next-generation flow cytometry and evaluated its clinical impact in 199 myeloma patients who underwent an ASCT. Contamination (con+) was detected in 79/199 patients at a median level 2 × 10^-5. Its presence and levels were correlated with response to induction treatment, with 94%, 71% and 43% achieving CR, VGPR and PR, respectively. Importantly, con+ grafts conferred 2-fold and 2.8-fold higher patient-risk of not achieving or delaying reaching CR (4 vs. 11 months) and MRD negativity (5 vs. 18 months) post ASCT, respectively. Our data also provide evidence of a potentially skewed bone marrow (BM) reconstitution due to unpurged grafts, since con+ derived BM had significantly higher prevalence of memory B cells. These data, together with the absence of significant associations with baseline clinical features, highlight graft contamination as a potential biomarker with independent prognostic value for deeper responses, including MRD negativity. Longer follow-up will reveal if this corresponds to PFS or OS advantage.

Responses in multiple myeloma should be assigned according to serum, not urine, free light chain measurements

The most recent update to the International Myeloma Working Group consensus criteria places a strong emphasis on the need for more sensitive haematological markers of response driven by the success of novel therapies. One such marker is serum free light chain (sFLC) analysis, which was first incorporated into the definition of stringent complete response in 2006. However, over the past decade there has been some reluctance to extend the role of the sFLC assays to replace 24 h urine electrophoresis for monitoring multiple myeloma (MM). In this review, we lay out the evidence in favour of serum over urine for monoclonal FLC measurements and propose modified criteria for response assignment in myeloma.

Elevated pre-transplant C-reactive protein identifies a high-risk subgroup in multiple myeloma patients undergoing delayed autologous stem cell transplantation

The significance of elevated C-reactive protein (CRP) prior to autologous stem cell transplantation (ASCT) in multiple myeloma (MM) has not been studied. We analyzed 1111 MM patients who underwent ASCT at Mayo Clinic from 2007 to 2015. A total of 840 patients (76%) received early ASCT (⩽12 months from diagnosis) and 271 patients (24%) received delayed ASCT (>12 months from diagnosis). Elevated CRP (> upper normal limit (8 mg/L)) was seen in 14% and 22% of patients undergoing early and delayed ASCT, respectively (P=0.003). There was no correlation of CRP with pre-transplant response, bone marrow plasma cell percentage or labeling index. Patients with an elevated CRP had a higher likelihood of having circulating plasma cells prior to ASCT (33 vs 19%; P<0.001). In the early ASCT cohort, the median overall survival (OS) in patients with normal and elevated CRP was not reached and 91 months respectively (P=0.011). In the delayed ASCT cohort, the median OS in respective groups were 73 and 30 months respectively (P<0.001), with elevated CRP being an independent prognostic marker on multivariate analysis (hazard ratio 2.0; 95% confidence interval, 1.0-3.8; P=0.045). Elevated pre-transplant CRP identifies a high-risk population especially in patients undergoing delayed ASCT and should be incorporated in the pre-transplant evaluation.

Glycosylation-Based Serum Biomarkers for Cancer Diagnostics and Prognostics

Cancer is the second most common cause of death in developed countries with approximately 14 million newly diagnosed individuals and over 6 million cancer-related deaths in 2012. Many cancers are discovered at a more advanced stage but better survival rates are correlated with earlier detection. Current clinically approved cancer biomarkers are most effective when applied to patients with widespread cancer. Single biomarkers with satisfactory sensitivity and specificity have not been identified for the most common cancers and some biomarkers are ineffective for the detection of early stage cancers. Thus, novel biomarkers with better diagnostic and prognostic performance are required. Aberrant protein glycosylation is well known hallmark of cancer and represents a promising source of potential biomarkers. Glycoproteins enter circulation from tissues or blood cells through active secretion or leakage and patient serum is an attractive option as a source for biomarkers from a clinical and diagnostic perspective. A plethora of technical approaches have been developed to address the challenges of glycosylation structure detection and determination. This review summarises currently utilised glycoprotein biomarkers and novel glycosylation-based biomarkers from the serum glycoproteome under investigation as cancer diagnostics and for monitoring and prognostics and includes details of recent high throughput and other emerging glycoanalytical techniques.