Makarova, Olga V.

An all-in-one Circulating Tumor Cell (CTC) isolation platform with streamlined multiplex integration of proteomic and genomic clinical testing.

Abstract Background: Blood-based biopsies can be used as a non-invasive method to recover both Circulating Tumor Cells (CTCs) 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 engulf tumor cells/debris. CAMLs are identified by their large size, 30-300 microns, and aberrant nuclear structure. We studied the peripheral blood of cancer patients to ascertain the prevalence, specificity and sensitivity of CAMLs in relation to their disease status at presentation, including a variety of benign and malignant diseases. 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: CellSieveTM microfilters were used to isolate CAMLs from 7.5 mL of whole peripheral blood. The pore size of CellSieveTM is 7 microns, 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, CD14, and CD45. CAMLs were defined as enlarged, multinuclear cells with diffuse cytoplasmic cytokeratin staining, and/or CD14+, and/or CD45+. CTCs were defined as filamentous cytokeratin cells that are CD45-. Study 1: Blinded peripheral blood samples from 61 cancer patients were tested, including Stage I-IV breast, pancreatic, lung and prostate cancers, and newly diagnosed, untreated patients. Non-blinded blood samples from 30 healthy volunteers served as controls. Study 2: Double blinded peripheral blood samples from 20 patients with abnormal mammogram results were drawn at time of tissue biopsy and screened. After analysis, unblinding showed a distribution of malignant breast disease (n = 10), benign (n = 8), or atypical hyperplasia (AH) (n = 2). Results: Study 1: CAMLs were found in 94% patients with Stage III/IV cancers, 87% with Stage I/II cancers, and 89% of all patients, regardless of cancer type. Specifically, CAMLs were found in 77% of prostate, 100% of pancreatic, 80% of lung, and 100% of breast patient samples. CAMLs were not found in healthy control samples (sensitivity: 84-96%, Specificity: 100%, PPV: 100%, NPV: 88-97%). Study 2: CAMLs were found in 8 patients with malignant disease, 2 with benign disease, and 2 with AH (sensitivity: 80%, Specificity: 75%, PPV: 80%, NPV: 75%) 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 potentially pre-malignant lesions. 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. Preliminary data from a double blind breast cancer study suggests that CAMLs may differentiate between benign and malignant breast diseases. Citation Format: Daniel Adams, Katherine Alpaugh, Massimo Cristofanilli, Stuart Martin, Saranya Chumsri, Raymond C. Bergen, Susan Tsai, Martin Edelman, Peixuan Zhu, Shuhong Li, Olga V. Makarova, Platte T. Amstutz, Cha-Mei Tang, Jeffrey R. Marks. Cancer associated macrophage-like cells as a blood-based biomarker for the screening of solid tumors. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5165. doi:10.1158/1538-7445.AM2015-5165

Abstract Background: Renal cell carcinoma (RCC) is the most common type of kidney cancer responsible for ∼80% of kidney cancer cases. Circulating tumor cells (CTCs) are emerging as an important prognostic and predictive biomarker in several types of metastatic cancers. However, methods for CTC detection that target only EpCAM and/or cytokeratin (CK) to enrich CTCs, may fail to recognize the CTCs in clear cell RCC (ccRCC) because ccRCC lacks expression of EpCAM. The objective of this study was to develop a new technology capable of detecting CTCs including those with a mesenchymal phenotype in metastatic RCC. Methods: Blood samples from patients affected by metastatic RCC were provided by Mayo Clinic Arizona and analyzed by Creatv MicroTech. CellSieveTM microfilters, which have 7 µm diameter pores in a uniform array, with 160,000 pores in a 9 mm diameter area, were used for separation of CTCs in the blood specimen. 7.5 mL of whole blood was diluted in the prefixation buffer and filtered through the microfilter. Clinical immunohistochemical markers for RCC such as CD10 and vimentin were used to identify candidate CTCs. The cells collected on the filter were fixed, permeabilized, and stained with DAPI and fluorescent antibodies specific to CD10, vimentin, and CD45. The assay protocol was developed using three RCC cell lines, 786-O, Caki-1, and Caki-2, and validated using blood samples from patients with metastatic RCC. Results: The capture efficiencies for 786-O, Caki-1, and Caki-2 cell lines were determined to be 98%, 98% and 97%, respectively. On-filter antibody staining revealed heterogeneous expressions of vimentin and CD10 in RCC cells. Patient samples were collected in duplicate CellSaveTM tubes and processed one day later. A CD10+/vimentin+/CD45- cell population was detected in blood samples with enumeration ranging from 4 to 86 cells/7.5 mL of blood. We found that the RCC CTC profile was distinct from other types of cancers. The typical CTCs display abnormal morphology, including large nuclei (typically 15-30 µm in size), irregular cell size and shape, and high nucleus-to-cytoplasm ratio. Although CD10 and vimentin antibodies have cross-reactivity with white blood cells (WBC), the CTCs could be distinguished from WBC based on morphology, cell size and CD45- staining. Conclusions: We demonstrated that the CellSieveTM microfiltration assay is a very simple and efficient method to isolate a CD10+/vimentin+/CD45- cell population from patients affected by metastatic ccRCC. Future studies include fluorescence in situ hybridization to confirm loss of 3p, a molecular event that occurs in >90% of ccRCC. We are also analyzing blood samples from patients treated with tyrosine kinase inhibitors to determine if cell enumeration is predictive of response to treatment. This technology might greatly facilitate detection of EpCAM negative ccRCC CTCs. The clinical significance of these unusual, large, rod-shaped, naked nuclei require further molecular characterization. Citation Format: Peixuan Zhu, Thai Ho, Erik P. Castle, Richard W. Joseph, Melissa L. Stanton, Shuhong Li, Daniel Adams, Olga V. Makarova, Platte T. Amstutz, Cha-Mei Tang. Isolation and identification of circulating tumor cells in renal cell carcinoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3081. doi:10.1158/1538-7445.AM2014-3081