Chikamatsu, Kazuaki

3053 Background: Recently, early studies have identified circulating stromal cells (CStCs), i.e. Cancer Associated Macrophage-Like cells (CAMLs), in patients (pts) with newly diagnosed invasive cancers, which are phagocytic myeloid immune cells emanating from primary tumors. However, no study has evaluated CAMLs as a pan solid tumor screening tool nor their clinical impact on pt outcomes. We analyzed the blood of untreated newly diagnosed cancer pts (n=441), or in non-malignant conditions (i.e. pancreatic cysts, n=77), or healthy controls (n=100). We found that CAMLs are prevalent (82%) in cancer pt blood, absent in healthy controls (0%) and less common in non-malignant conditions (36%), with correlations to worse clinical outcomes. Methods: Anonymized peripheral blood was taken from n=441 pts before or after confirmation of invasive malignancy [stage I (n=105), stage II (n=125), stage III (n=114), stage IV (n=97) with pathologically confirmed lung (n=84), pancreas (n=61), breast (n=73), prostate (n=65), esophageal (n=34), Renal Cell (n=29), Sarcoma (n=27), or Other (n=68). In addition, anonymized blood was taken from pts with untreated non-malignant conditions including benign breast masses (n=19), Lupus (n=11), liver Cirrhosis (n=6), rising PSA (n=24), or other benign mass (n=17); and from healthy control volunteers (n=100). CAMLs were isolated by CellSieve microfiltration, defined as enlarged polyploid cells with cytokeratin+ and/or CD45/CD14+. Pts were monitored for 0-8 years (median=2.6) for progression free survival (PFS) and overall survival (OS). Results: CAMLs were found in 82% of all cancer pts averaging 5.4 CAMLs, specifically, in 66% of Stage I, 85% Stage II, 84% Stage III, and 92% Stage IV. No CAMLs were found in any healthy controls, but were in 36% of non-malignant pts. CAML sensitivity in cancer vs healthy was 82% (CI95% 78-85%), specificity=100% (CI95% 96-100%), PPV=100% (CI95% 99-100%), NPV=55% (CI95% 50-60%). CAML sensitivity in cancer vs benign was 82% (CI95% 78-85%), specificity=64% (CI95% 32-44%), PPV=93% (CI95% 90-95%), NPV=38% (CI95% 32-44%). CAML presence was significantly associated with worse PFS (HR=2.0, 95%CI 1.4-2.9, p<0.0001) & OS (HR=2.2, 95%CI 1.4-3.3, p=0.0004), with engorged phagocytic CAMLs (>50um), highly significant for worse PFS (HR=3.3, 95%CI 2.5-4.5, p<0.0001) & OS (HR=3.0, 95%CI 2.1-4.3, p<0.0001). Further, in benign pts positive for CAMLs, 2 pts were in situ, 16 had histologies with increased cancer risk (i.e. IPMN, atypical hyperplasia), and 5 pts died within 3 years. Conclusions: CAMLs appear to be a highly sensitive blood based biomarker that can identify invasive carcinoma in all stages of cancer regardless of subtype, but are not found in healthy controls & rare in non-malignant conditions. Further, enlarged phagocytic CAMLs appeared to correlate with shorter PFS and OS prior to treatment induction.

3535 Background: Peripheral blood allows for a simple non-invasive method for isolating various cancer associated circulating stromal cells (CStCs) which may predict for cancer presence. Cancer Associated Macrophage-Like cells (CAMLs), a specific CStC, are phagocytic myeloid cells that derive from an immunological response to cancer and emanate from primary tumors. Using a filtration platform we screened the peripheral blood of untreated newly diagnosed cancer patients (n = 308) for CAMLs. In parallel, we screened patients with newly diagnosed non-malignant diseases, i.e. lupus, benign cysts, etc. (n = 39), and healthy control samples (n = 76). We found that CAMLs are highly prevalent (87%) in the blood of cancer patients, but uncommon in non-malignant conditions (20%) & absent in healthy individuals (0%). Methods: Anonymized peripheral blood were taken from 308 cancer patients after confirmation of invasive malignancy [stage I (n = 76), stage II (n = 73), stage III (n = 72), stage IV (n = 65) and unstaged non-metastatic (n = 22)] with pathologically confirmed lung (n = 65), pancreas (n = 53), breast (n = 52), prostate (n = 40), esophageal (n = 30), renal cell (n = 18), hepatocellular (n = 15), neuroblastoma (n = 10), melanoma (n = 8), and other (n = 17). Further, anonymized blood was taken from patients with untreated non-malignant conditions including benign breast masses (n = 19), lupus (n = 11), liver cirrhosis (n = 5), benign prostatic hyperplasia (BPH) (n = 3), and viral infection (n = 1); or from healthy control volunteers (n = 76). CAMLs were isolated from whole peripheral blood by the CellSieve™ microfiltration technique and defined as enlarged, multinuclear cells with cytokeratin and/or CD45/CD14 positive. Results: CAMLs were found in 87% of all cancer patients regardless of stage, ~5.4 CAMLs/7.5mL blood. Specifically, CAMLs were found in 80% of Stage I, 90% Stage II, 89% Stage III, and 97% Stage IV patients. No CAMLs were found in any healthy controls, but were found in 26% of benign breast masses, 18% of lupus, 0% of BPH and 0% of cirrhosis. In total, CAML sensitivity in cancer vs healthy was 87% (CI95% 82-90%), specificity = 100% (CI95% 95-100%), PPV = 100% (CI95% 100%), NPV = 67% (CI95% 58-71%). CAML sensitivity in cancer vs benign was 87% (CI95% 82-90%), specificity = 80% (CI95% 64-91%), PPV = 97% (CI95% 95-98%), NPV = 43% (CI95% 35-51%). Conclusions: CAMLs, a Circulating Stromal Cell subtype, is a sensitive blood based biomarker found in all stages of cancer that is rare in non-malignant conditions and absent in healthy individuals.