Immune checkpoint therapy with PD-1 blockade has emerged as an effective therapy for many advanced cancers; however, only a small fraction of patients achieve durable responses. To date, there is no validated blood-based means of predicting the response to PD-1 blockade. We report that Bim is a downstream signaling molecule of the PD-1 pathway, and its detection in T cells is significantly associated with expression of PD-1 and effector T cell markers. High levels of Bim in circulating tumor-reactive (PD-1 + CD11a hi CD8 + ) T cells were prognostic of poor survival in patients with metastatic melanoma who did not receive anti–PD-1 therapy and were also predictive of clinical benefit in patients with metastatic melanoma who were treated with anti–PD-1 therapy. Moreover, this circulating tumor-reactive T cell population significantly decreased after successful anti–PD-1 therapy. Our study supports a crucial role of Bim in both T cell activation and apoptosis as regulated by PD-1 and PD-L1 interactions in effector CD8 + T cells. Measurement of Bim levels in circulating T cells of patients with cancer may provide a less invasive strategy to predict and monitor responses to anti–PD-1 therapy, although future prospective analyses are needed to validate its utility.
The use of programmed cell death 1 ligand 1 (PD‐L1) as a predictive biomarker to select patients to receive programmed cell death 1 (PD‐1) or PD‐L1 inhibitors in non‐small cell lung cancer (NSCLC) is limited by the definitions of positivity, interassay agreement, and intra‐ and intertumoral heterogeneity of expression. Although PD‐L1 expression enriches for responses, the lack of expression does not exclude clinical benefit.
Heterogeneity of Programmed Cell Death Ligand 1 Expression in Multifocal Lung Cancer
Abstract Background: The prognosis for stage III melanoma is variable, with the 5-year survival ranging from 23-87%. Previous studies have demonstrated both immune cell activation and dysfunction within the sentinel lymph node (SLN) of melanoma patients. We hypothesize that differences within the host response, specifically the immune cell profile of the SLN, may predict the heterogeneous behavior of stage III melanoma. Methods: A retrospective review of clinically node negative patients undergoing a SLN biopsy at our institution was undertaken. Thirty four SLN positive cases in which the patients also underwent a complete lymph node dissection were identified and the archived FFPE SLN blocks were obtained. A single tumor positive SLN was selected and immunohistochemistry was performed for dendritic cell markers (CD123, CD86, CD11c and HLA-DR), cytotoxic T cells (CD8), anergic T cells (PD-1) and regulatory T cells (Foxp3). Slides were digitized and analyzed for percent of the SLN staining positive for each respective marker using IHCscore. These findings were correlated with risk of further non-SLN disease in the same nodal basin as well as effect on disease-free and overall survival. Results: The SLN exhibited expression of both immune activation (CD8, CD86, and CD11c) and immune suppressive (CD123, PD-1 and Foxp3) markers. HLA-DR expression was significantly higher in females (52.07% vs. 42.32%, p=0.02). No other immune marker was associated with any baseline demographic or clinical variable. Median disease-free survival and overall survival was 6 months and not yet reached and 16 months and not yet reached for patients with and without non-SLN involvement, respectively; however, no difference was noted in any of the SLN immune markers between patients with and without non-SLN involvement. Increased CD8 expression in the SLN was associated with an improvement in disease-free survival (HR 0.94 p = 0.048) but not overall survival (HR 0.93 p = 0.07). In two variable multivariate analyses, CD8 expression remained independent for disease-free survival when adjusted for Breslow depth but not non-SLN involvement. The median disease-free survival for patients with low CD8 expression within the SLN was 19.5 months and median disease-free survival has not been reached in those with high CD8 expression in the SLN after a median of 59 months follow up (log-rank p = 0.05). Conclusion: Previous reports suggest T cell infiltration of melanoma tumors is an important prognostic factor. In this study we found that CD8 T cell accumulation within the SLN was associated with a disease-free survival advantage. Cytotoxic T cell accumulation within the SLN declines early in melanoma and the degree of CD8 depletion corresponds to the risk of disease recurrence. These findings support a key role for effector T cells in the control of melanoma progression. Citation Format: Travis E. Grotz, Aaron S. Mansfield, James W. Jakub, Svetomir N. Markovic, Tina J. Hieken. Immune cell profile of the SLN has prognostic value in stage III melanoma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1266. doi:10.1158/1538-7445.AM2013-1266
Abstract PD02-05: Comparison of fluorescence in situ hybridization (FISH) and dual-ISH (D-ISH) in the determination of HER2 status
Abstract Introduction: The appropriate assessment of HER2 amplification status is critical to determining which patients should receive HER2-directed therapy. An alternative to FISH is D-ISH (Ventana Medical Systems Tucson, Arizona) which utilizes chromogenic HER2 and chromosome 17 probes. Both FISH and D-ISH utilize formalin-fixed, paraffin-embedded (FFPE) human breast cancer tissue specimens. D-ISH has two principle advantages over FISH: it can be visualized using light microscopy and after analysis the specimens can be archived. Methods: We tested 250 samples with FISH and with D-ISH. Fifty specimens were controls: 25 cases with no HER2 or CEP17anomaly and 25 cases with HER2 amplification. There were also 200 test subjects of 50 cases each of chromosome 17 aneusomy, HER2 deletion (HER2/CEP17 ratio <0.8), HER2 duplication (HER2/CEP17 ratio 1.3–1.8), and equivocal results (HER2/CEP17 ratios between 1.8 and 2.2). FISH (Abbott Molecular) and D-ISH analysis were performed using methods described in the appropriate clinical kit package inserts, with the following exception: Four cases with CEP17 and HER2 co-amplification were also included and for FISH analysis these cases were reflexed to the use of chromosome 17 control probe (D17S122). Results: Four samples failed testing by D-ISH. There was a 63% (155/246) concordance between FISH and D-ISH by anomaly (aneusomy, duplication, deletion, etc.) and an 83% concordance by amplification status (non-amplified, equivocal, and amplified). D-ISH detected 18 (62%) of F-ISH-amplified cases. D-ISH resulted in lower estimates of HER2/CEP17 ratios than FISH, and many cases that were equivocal by FISH were normal by D-ISH. D-ISH did not detect HER2 amplification in any of the four HER2 and CEP17 co-amplified cases. Conclusions: We observed a lower concordance rate between FISH and D-ISH than the ∼95% rate in the D-ISH package insert. This lower concordance rate is likely a result of how this study was designed: it was biased toward common chromosome 17 anomalies and difficult specimens. Such specimens comprise about 60% of our current clinical HER2 biomarker practice. D-ISH may underestimate the HER2/CEP17 ratio, or FISH may overestimate this ratio. D-ISH also does not reliably detect HER2 amplification when the centromere of chromosome 17 is also co-amplifed. Compared to FISH, in this study cohort D-ISH had a significant false negative rate for the detection of HER2 amplification. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr PD02-05.