Cancer Associated Macrophage-Like Cells in the Early Detection of Solid Tumors from Numerous Malignancies

摘要

Background: Blood-based biopsies can be used as a non-invasive method to recover both Circulating Tumor Cells and Circulating Cancer Associated Macrophage-Like cells (CAMLs) from the blood of cancer patients. CAMLs are a newly-defined circulating immune cell type, described as a subtype of circulating stromal cells, known to specifically circulating in patients with malignant disease. We studied the peripheral blood of 100 cancer patients to ascertain the prevalence, specificity and sensitivity of CAMLs in relation to their disease status at presentation. We compared a variety of benign and malignant diseases, along with matched healthy control blood samples. We supply evidence that this previously unidentified circulating cell can be used as a screening tool to detect solid tumors in numerous malignancy subtypes in all disease stages. Methods: CellSieve? microfilters were used to isolate CAMLs from 7.5 mL of whole peripheral blood. The pore size of CellSieve? is 7 microns is capable of isolating both CTCs and CAMLs based on size. Collected cells were fixed, permeabilized, and stained with DAPI and antibodies against cytokeratin 8, 18 and 19, and CD45. CAMLs were defined as enlarged, multinuclear cells with diffuse cytoplasmic cytokeratin staining, CD14+, or CD45+. CTCs were defined as filamentous cytokeratin cells that are CD45-. We ran a prospective blinded study to isolate CAMLs from patients with known invasive carcinomas (n=100), age matched healthy control samples (n=40) and patients with benign non-malignant conditions (n=21). Results: CAMLs were found in 92% patients with confirmed malignant disease. Specifically in 81% of stage I patients, 97% of stage II patients, 87% of Stage III patients, and, and 92% of Stage IV patients, regardless of cancer type. Specifically, CAMLs were found in 79% of prostate, 98% of pancreatic, 85% of lung, and 98% of breast patient samples. CAMLs were found in 24% (n=5/21) of patients with benign conditions and in none of the healthy control samples (sensitivity: 92%, Specificity: 100%, PPV: 100%, NPV: 88-99%). Conclusions: We present evidence that CAMLs can be used as a non-invasive blood based biopsy, to detect the anatomical presence of solid malignancies and partially differentiate benign non-malignant conditions. The presence of CAMLs in newly diagnosed patient samples suggests their use as a blood biomarker for early stage cancer screening in a broad population. While preliminary data from a validation study is needed, this initial study suggests that CAMLs differentiate between benign and malignant breast diseases from persons without malignant disease.