Abstract 2631: Cancer associated macrophage-like (CAMLs) cells in blood predict progression and survival for all stages of solid tumors
Authors: Adams Daniel L. , Lin Steven H. , Alpaugh R. Katherine , Ho Thai , Marks Jeffrey R. , Martin Stuart S. , Tsai Susan , Chumsri Saranya , Tang Cha-Mei , Cristofanilli Massimo , Bergan Raymond 
Published: August 2018

Background: We previously demonstrated that cancer associated macrophage-like cells (CAMLs) are cancer specific giant polyploid cells circulating in the blood of patients with solid tumors. Building on our initial discovery, others have shown that these hyperploidy cells are an innate immune response that is associated with decreased survival. However to date, no studies have been done to elucidate their clinical significance as in relation to the various stages of malignant disease. We established a 4 year prospective study of 315 patients from a variety of solid tumors (breast, prostate, lung, renal cell, pancreas, and esophageal) comparing the morphological properties of CAMLs in both early and late stage disease as they relate to progression free and overall survival (PFS/OS). These data suggest that CAML size appears have a strong negative correlation with progression and survival of cancer patients, irregardless of stage of disease, indicating their possible use as a non-invasive blood based biomarker in solid tumors.

Methods: A prospective multi-institutional study used anonymized peripheral blood from 315 cancer patients [stage I (n=62), stage II (n=72), stage III (n=69) & stage IV (n=106)] from subjects with breast (n=59), esophageal (n=27), lung (n=59), renal cell carcinoma (n=37), prostate (n=74), pancreas cancers (n=59). CAMLs were isolated by the CellSieve™ microfiltration technique at 5 institutions and stained for cytokeratin 8, 18, & 19, CD14 and CD45. After imaging, a size based threshold ≥50µm was used to separate the patient cohorts, based on previously published assessments.

Results: At least one CAML was found in 92% of cancer patients (n=289/315), with the lowest sensitivity in stage 1 (86%), followed by stage 2 (90%), stage 3 (97%) and stage 4 (95%). The property of CAML size was then evaluated. Overall, CAMLs of &lt;50µm in size had superior PFS (HR: 3.8; 95% CI 2.8-5.3; p&lt;0.001) and OS (HR=3.8; 95% CI 2.6-5.7;p&lt;0.001) than those with ≥50 µm CAMLs. By each stage individually, stage 1 (PFS HR=7.5; 95% CI 3.2-17.7; p&lt;0.001), stage II (PFS; HR=4.1; 95% CI 1.9-8.8; p&lt;0.001), stage III (PFS HR=3.1; 95% CI 1.7-5.7; p=0.007), and stage IV (PFS HR=2.7; 95% CI 1.6-4.4; p&lt;0.001).

Conclusions: In this first large scale prospective study of the clinical utility of CAMLs, it appears that they are present in every stages of invasive solid tumor malignancies, with prevalence increasing with stage. Interestingly decreased CAML size was found to be associated with improved outcome and longer PFS. These data suggest that CAML detection and size assessment constitute a new real time predictor of progression, and survival in both early and late stage disease indicating the need for additional validation studies.

Citation Format: Daniel L. Adams, Steven H. Lin, R. Katherine Alpaugh, Thai Ho, Jeffrey R. Marks, Stuart S. Martin, Susan Tsai, Saranya Chumsri, Cha-Mei Tang, Massimo Cristofanilli, Raymond Bergan. Cancer associated macrophage-like (CAMLs) cells in blood predict progression and survival for all stages of solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2631.