Browsing by Author "Strickler, John H"

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    ItemOpen Access
    Clinical applications of liquid biopsies in gastrointestinal oncology.
    (Journal of gastrointestinal oncology, 2016-10) Zhu, Jason; Strickler, John H
    "Liquid biopsies" are blood based assays used to detect and analyze circulating tumor products, including circulating tumor cells (CTCs), circulating tumor DNA (ctDNA), circulating messenger RNA (mRNA), circulating microRNA (miRNA), circulating exosomes, and tumor educated platelets (TEP). For patients with gastrointestinal (GI) malignancies, blood based biopsies may offer several advantages. First, tumor tissue samples are often challenging to procure, and when obtainable, are often insufficient for genomic profiling. Second, blood based assays offer a real-time overview of the entire tumor burden, and allow anatomically unbiased genomic profiling. Third, given the convenience and relative safety of liquid biopsies, this technology may facilitate identification of genomic alterations that confer sensitivity and resistance to targeted therapeutics. This review will assess the clinical applications of circulating tumor products for patients with GI tumors.
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    Concordance Between Genomic Alterations Detected by Tumor and Germline Sequencing: Results from a Tertiary Care Academic Center Molecular Tumor Board.
    (The oncologist, 2023-01) Green, Michelle F; Watson, Catherine H; Tait, Sarah; He, Jie; Pavlick, Dean C; Frampton, Garrett; Riedel, Jinny; Plichta, Jennifer K; Armstrong, Andrew J; Previs, Rebecca A; Kauff, Noah; Strickler, John H; Datto, Michael B; Berchuck, Andrew; Menendez, Carolyn S

    Objective

    The majority of tumor sequencing currently performed on cancer patients does not include a matched normal control, and in cases where germline testing is performed, it is usually run independently of tumor testing. The rates of concordance between variants identified via germline and tumor testing in this context are poorly understood. We compared tumor and germline sequencing results in patients with breast, ovarian, pancreatic, and prostate cancer who were found to harbor alterations in genes associated with homologous recombination deficiency (HRD) and increased hereditary cancer risk. We then evaluated the potential for a computational somatic-germline-zygosity (SGZ) modeling algorithm to predict germline status based on tumor-only comprehensive genomic profiling (CGP) results.

    Methods

    A retrospective chart review was performed using an academic cancer center's databases of somatic and germline sequencing tests, and concordance between tumor and germline results was assessed. SGZ modeling from tumor-only CGP was compared to germline results to assess this method's accuracy in determining germline mutation status.

    Results

    A total of 115 patients with 146 total alterations were identified. Concordance rates between somatic and germline alterations ranged from 0% to 85.7% depending on the gene and variant classification. After correcting for differences in variant classification and filtering practices, SGZ modeling was found to have 97.2% sensitivity and 90.3% specificity for the prediction of somatic versus germline origin.

    Conclusions

    Mutations in HRD genes identified by tumor-only sequencing are frequently germline. Providers should be aware that technical differences related to assay design, variant filtering, and variant classification can contribute to discordance between tumor-only and germline sequencing test results. In addition, SGZ modeling had high predictive power to distinguish between mutations of somatic and germline origin without the need for a matched normal control, and could potentially be considered to inform clinical decision-making.
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    Development of a Novel c-MET-Based CTC Detection Platform.
    (Mol Cancer Res, 2016-06) Zhang, Tian; Boominathan, Rengasamy; Foulk, Brad; Rao, Chandra; Kemeny, Gabor; Strickler, John H; Abbruzzese, James L; Harrison, Michael R; Hsu, David S; Healy, Patrick; Li, Jing; Pi, Cinthia; Prendergast, Katherine M; Hobbs, Carey; Gemberling, Sarah; George, Daniel J; Hurwitz, Herbert I; Connelly, Mark; Garcia-Blanco, Mariano A; Armstrong, Andrew J
    UNLABELLED: Amplification of the MET oncogene is associated with poor prognosis, metastatic dissemination, and drug resistance in many malignancies. We developed a method to capture and characterize circulating tumor cells (CTC) expressing c-MET using a ferromagnetic antibody. Immunofluorescence was used to characterize cells for c-MET, DAPI, and pan-CK, excluding CD45(+) leukocytes. The assay was validated using appropriate cell line controls spiked into peripheral blood collected from healthy volunteers (HV). In addition, peripheral blood was analyzed from patients with metastatic gastric, pancreatic, colorectal, bladder, renal, or prostate cancers. CTCs captured by c-MET were enumerated, and DNA FISH for MET amplification was performed. The approach was highly sensitive (80%) for MET-amplified cells, sensitive (40%-80%) for c-MET-overexpressed cells, and specific (100%) for both c-MET-negative cells and in 20 HVs. Of 52 patients with metastatic carcinomas tested, c-MET CTCs were captured in replicate samples from 3 patients [gastric, colorectal, and renal cell carcinoma (RCC)] with 6% prevalence. CTC FISH demonstrated that MET amplification in both gastric and colorectal cancer patients and trisomy 7 with gain of MET gene copies in the RCC patient. The c-MET CTC assay is a rapid, noninvasive, sensitive, and specific method for detecting MET-amplified tumor cells. CTCs with MET amplification can be detected in patients with gastric, colorectal, and renal cancers. IMPLICATIONS: This study developed a novel c-MET CTC assay for detecting c-MET CTCs in patients with MET amplification and warrants further investigation to determine its clinical applicability. Mol Cancer Res; 14(6); 539-47. ©2016 AACR.
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    Pharmacological Wnt ligand inhibition overcomes key tumor-mediated resistance pathways to anti-PD-1 immunotherapy.
    (Cell reports, 2021-05) DeVito, Nicholas C; Sturdivant, Michael; Thievanthiran, Balamayooran; Xiao, Christine; Plebanek, Michael P; Salama, April KS; Beasley, Georgia M; Holtzhausen, Alisha; Novotny-Diermayr, Veronica; Strickler, John H; Hanks, Brent A
    While immune checkpoint blockade is associated with prolonged responses in multiple cancers, most patients still do not benefit from this therapeutic strategy. The Wnt-β-catenin pathway is associated with diminished T cell infiltration; however, activating mutations are rare, implicating a role for autocrine/paracrine Wnt ligand-driven signaling in immune evasion. In this study, we show that proximal mediators of the Wnt signaling pathway are associated with anti-PD-1 resistance, and pharmacologic inhibition of Wnt ligand signaling supports anti-PD-1 efficacy by reversing dendritic cell tolerization and the recruitment of granulocytic myeloid-derived suppressor cells in autochthonous tumor models. We further demonstrate that the inhibition of Wnt signaling promotes the development of a tumor microenvironment that is more conducive to favorable responses to checkpoint blockade in cancer patients. These findings support a rationale for Wnt ligand-focused treatment approaches in future immunotherapy clinical trials and suggest a strategy for selecting those tumors more responsive to Wnt inhibition.
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    Racial and ethnic disparities in genomic testing among lung cancer patients: a systematic review.
    (Journal of the National Cancer Institute, 2024-06) Meernik, Clare; Raveendran, Yadurshini; Kolarova, Michaela; Rahman, Fariha; Olunuga, Ebunoluwa; Hammond, Emmery; Shivaramakrishnan, Akhilesh; Hendren, Steph; Bosworth, Hayden B; Check, Devon K; Green, Michelle; Strickler, John H; Akinyemiju, Tomi

    Background

    Racial and ethnic disparities in genomic testing could exacerbate disparities in access to precision cancer therapies and survival-particularly in the context of lung cancer where genomic testing has been recommended for the past decade. However, prior studies assessing disparities in genomic testing have yielded mixed results.

    Methods

    We conducted a systemic review to examine racial and ethnic disparities in the use of genomic testing among lung cancer patients in the United States. Two comprehensive searches in PubMed, Embase, and Scopus were conducted (September 2022, May 2023). Original studies that assessed rates of genomic testing by race or ethnicity were included. Findings were narratively synthesized by outcome.

    Results

    The search yielded 2739 unique records, resulting in 18 included studies. All but 1 study were limited to patients diagnosed with non-small cell lung cancer. Diagnosis years ranged from 2007 to 2022. Of the 18 studies, 11 found statistically significant differences in the likelihood of genomic testing by race or ethnicity; in 7 of these studies, testing was lower among Black patients compared with White or Asian patients. However, many studies lacked adjustment for key covariates and included patients with unclear eligibility for testing.

    Conclusions

    A majority of studies, though not all, observed racial and ethnic disparities in the use of genomic testing among patients with lung cancer. Heterogeneity of study results throughout a period of changing clinical guidelines suggests that minoritized populations-Black patients in particular-have faced additional barriers to genomic testing, even if not universally observed at all institutions.