The Society for Immunotherapy of Cancer statement on best practices for multiplex immunohistochemistry (IHC) and immunofluorescence (IF) staining and validation.

OBJECTIVES: The interaction between the immune system and tumor cells is an important feature for the prognosis and treatment of cancer. Multiplex immunohistochemistry (mIHC) and multiplex immunofluorescence (mIF) analyses are emerging technologies that can be used to help quantify immune cell subsets, their functional state, and their spatial arrangement within the tumor microenvironment. METHODS: The Society for Immunotherapy of Cancer (SITC) convened a task force of pathologists and laboratory leaders from academic centers as well as experts from pharmaceutical and diagnostic companies to develop best practice guidelines for the optimization and validation of mIHC/mIF assays across platforms. RESULTS: Representative outputs and the advantages and disadvantages of mIHC/mIF approaches, such as multiplexed chromogenic IHC, multiplexed immunohistochemical consecutive staining on single slide, mIF (including multispectral approaches), tissue-based mass spectrometry, and digital spatial profiling are discussed. CONCLUSIONS: mIHC/mIF technologies are becoming standard tools for biomarker studies and are likely to enter routine clinical practice in the near future. Careful assay optimization and validation will help ensure outputs are robust and comparable across laboratories as well as potentially across mIHC/mIF platforms. Quantitative image analysis of mIHC/mIF output and data management considerations will be addressed in a complementary manuscript from this task force.

Clinical Utility of the Combined Positive Score for Programmed Death Ligand-1 Expression and the Approval of Pembrolizumab for Treatment of Gastric Cancer.

CONTEXT.­: Regulatory approval of pembrolizumab for treatment of gastric and gastroesophageal junction (G/GEJ) adenocarcinoma required a reproducible scoring method for use of programmed death ligand-1 (PD-L1) protein expression as a companion diagnostic to identify likely responders to therapy. OBJECTIVE.­: To develop an immunohistochemical scoring algorithm that includes PD-L1 expression for tumor and immune cells, that is, the combined positive score. DESIGN.­: Four previously treated tumor types in the KEYNOTE-012 and KEYNOTE-028 studies were analyzed descriptively with a version of the PD-L1 immunohistochemical 22C3 pharmDx assay labeled for investigational use only to determine the relative importance of PD-L1 expression in tumor versus immune cells as a biomarker for pembrolizumab response. A combined positive score was developed as a novel scoring method and was compared with the tumor proportion score in cohort 1 from the KEYNOTE-059 study (G/GEJ cancer). External reproducibility was assessed. RESULTS.­: Per combined positive score cutoff of 1 or more, the prevalence of PD-L1 expression in patients with G/GEJ cancer was 57.6% (148 of 257 patients), with reasonable enrichment of responses (odds ratio, 2.8). Per tumor proportion score cutoff of 1% or more, prevalence was 12.5% (32 of 257 patients), with minimal enrichment (odds ratio, 1.4). External reproducibility assessments demonstrated interpathologist overall agreement of 96.6% (591 of 612; 95% CI, 94.0%-98.7%) and intrapathologist overall agreement of 97.2% (595 of 612; 95% CI, 95.3%-98.9%). CONCLUSIONS.­: Combined positive score is a robust, reproducible PD-L1 scoring method that predicts response to pembrolizumab in patients with G/GEJ cancer. This novel scoring method supported US Food and Drug Administration approval of pembrolizumab as third-line therapy for G/GEJ cancer and has facilitated investigation in other indications.

Use of the 22C3 anti-programmed death-ligand 1 antibody to determine programmed death-ligand 1 expression in cytology samples obtained from non-small cell lung cancer patients.

BACKGROUND: Pembrolizumab monotherapy is a standard-of-care treatment for the first- and second-line treatment of advanced non-small cell lung cancer with programmed death-ligand 1 (PD-L1) tumor proportion score (TPS) values ≥ 50% and ≥ 1%, respectively. PD-L1 testing with the PD-L1 immunohistochemistry (IHC) 22C3 pharmDx companion assay has been validated on tumor tissue with the Dako Autostainer Link 48 (ASL48). 22C3 anti-PD-L1 antibody-based laboratory-developed tests (LDTs) compatible with other autostainers and cytology samples are essential to support pembrolizumab treatment decisions across institutions globally. METHODS: ASL48 and BenchMark Ultra LDTs were optimized for the evaluation of cytology samples through comparisons with cell lines with known PD-L1 expression levels (strong, moderate, and negative). The PD-L1 TPS was then evaluated for 70 paired biopsy and cytology samples (bronchial washes, n = 40; pleural effusions, n = 30) with these LDTs. Biopsy and cytology LDT TPS values were also compared with a subset of biopsy samples (n = 37) evaluated with the PD-L1 IHC 22C3 pharmDx assay on the ASL48. RESULTS: Intraclass correlation coefficients of 0.884 to 0.898 were observed for biopsy samples versus cytology samples with the ASL48 and BenchMark Ultra LDTs. Concordance was high, regardless of the TPS cut point (<1% vs ≥ 1% and <50% vs ≥ 50%), sample type (pleural effusion vs bronchial wash), or tumor histology (adenocarcinoma vs squamous cell carcinoma). Concordance was high for each LDT versus the PD-L1 IHC 22C3 pharmDx assay. CONCLUSIONS: ASL48 and BenchMark Ultra 22C3 antibody concentrate-based LDTs have been validated for PD-L1 testing in cytology samples, and they will support reliable, high-quality PD-L1 testing across regions globally. Cancer Cytopathol 2018;126:264-74. © 2018 American Cancer Society.

Correction: Use of the 22C3 anti-PD-L1 antibody to determine PD-L1 expression in multiple automated immunohistochemistry platforms.

[This corrects the article DOI: 10.1371/journal.pone.0183023.].

Use of the 22C3 anti-PD-L1 antibody to determine PD-L1 expression in multiple automated immunohistochemistry platforms.

BACKGROUND: For non-small cell lung cancer (NSCLC), treatment with pembrolizumab is limited to patients with tumours expressing PD-L1 assessed by immunohistochemistry (IHC) using the PD-L1 IHC 22C3 pharmDx (Dako, Inc.) companion diagnostic test, on the Dako Autostainer Link 48 (ASL48) platform. Optimised protocols are urgently needed for use of the 22C3 antibody concentrate to test PD-L1 expression on more widely available IHC autostainers. METHODS: We evaluated PD-L1 expression using the 22C3 antibody concentrate in the three main commercially available autostainers Dako ASL48, BenchMark ULTRA (Ventana Medical Systems, Inc.), and Bond-III (Leica Biosystems) and compared the staining results with the PD-L1 IHC 22C3 pharmDx kit on the Dako ASL48 platform. Several technical conditions for laboratory-developed tests (LDTs) were evaluated in tonsil specimens and a training set of three NSCLC samples. Optimised protocols were then validated in 120 NSCLC specimens. RESULTS: Optimised protocols were obtained on both the VENTANA BenchMark ULTRA and Dako ASL48 platforms. Significant expression of PD-L1 was obtained on tissue controls with the Leica Bond-III autostainer when high concentrations of the 22C3 antibody were used. It therefore was not tested on the 120 NSCLC specimens. An almost 100% concordance rate for dichotomized tumour proportion score (TPS) results was observed between TPS ratings using the 22C3 antibody concentrate on the Dako ASL48 and VENTANA BenchMark ULTRA platforms relative to the PD-L1 IHC 22C3 pharmDx kit on the Dako ASL48 platform. Interpathologist agreement was high on both LDTs and the PD-L1 IHC 22C3 pharmDx kit on the Dako ASL48 platform. CONCLUSION: Availability of standardized protocols for determining PD-L1 expression using the 22C3 antibody concentrate on the widely available Dako ASL48 and VENTANA BenchMark ULTRA IHC platforms will expand the number of laboratories able to determine eligibility of patients with NSCLC for treatment with pembrolizumab in a reliable and concordant manner.

PD-L2 Expression in Human Tumors: Relevance to Anti-PD-1 Therapy in Cancer.

Purpose: Tumor-associated PD-L1 expression is predictive of clinical response to PD-1-directed immunotherapy. However, PD-L1-negative patients may also respond to PD-1 checkpoint blockade, suggesting that other PD-1 ligands may be relevant to the clinical activity of these therapies. The prevalence of PD-L2, the other known ligand of PD-1, and its relationship to response to anti-PD-1 therapy were evaluated.Experimental Design: PD-L2 expression was assessed in archival tumor tissue from seven indications using a novel immunohistochemical assay. In addition, relationships between clinical response and PD-L2 status were evaluated in tumor tissues from patients with head and neck squamous cell carcinoma (HNSCC) with recurrent or metastatic disease, treated with pembrolizumab.Results: PD-L2 expression was observed in all tumor types and present in stromal, tumor, and endothelial cells. The prevalence and distribution of PD-L2 correlated significantly with PD-L1 (P = 0.0012-<0.0001); however, PD-L2 was detected in the absence of PD-L1 in some tumor types. Both PD-L1 and PD-L2 positivity significantly predicted clinical response to pembrolizumab on combined tumor, stromal and immune cells, with PD-L2 predictive independent of PD-L1. Response was greater in patients positive for both PD-L1 and PD-L2 (27.5%) than those positive only for PD-L1 (11.4%). PD-L2 status was also a significant predictor of progression-free survival (PFS) with pembrolizumab independent of PD-L1 status. Longer median times for PFS and overall survival were observed for PD-L2-positive than PD-L2-negative patients.Conclusions: Clinical response to pembrolizumab in patients with HNSCC may be related partly to blockade of PD-1/PD-L2 interactions. Therapy targeting both PD-1 ligands may provide clinical benefit in these patients. Clin Cancer Res; 23(12); 3158-67. ©2017 AACR.

Safety and activity of pembrolizumab in patients with locally advanced or metastatic urothelial cancer (KEYNOTE-012): a non-randomised, open-label, phase 1b study.

BACKGROUND: PD-1 and its ligands are expressed in urothelial cancer, and findings have shown that inhibition of the PD-1 pathway has clinical benefit. We aimed to assess the safety and activity of an anti-PD-1 antibody pembrolizumab in patients with locally advanced or metastatic urothelial cancer. METHODS: This study was part of the non-randomised, multi-cohort, open-label, phase 1b KEYNOTE-012 basket trial. We enrolled patients aged 18 years and older with a histologically or cytologically confirmed diagnosis of locally advanced or metastatic urothelial cancer, including cancers of the renal pelvis, ureter, bladder, or urethra, from eight hospitals in the USA and Israel. Patients were required to have at least 1% PD-L1 expression detected on the tumour cells or in tumour stroma, as determined by immunohistochemistry. Patients were given 10 mg/kg intravenous pembrolizumab every 2 weeks until disease progression, unacceptable toxic effects, or the end of the study (ie, 24 months of treatment). Primary endpoints were safety and overall response (defined by Response Evaluation Criteria In Solid Tumors [RECIST] version 1.1), as assessed by a masked, independent central review. Safety was assessed in patients who received one or more doses of pembrolizumab (all-patients-as-treated population); activity was assessed in patients who received pembrolizumab, had measurable disease at baseline, and had one or more post-baseline scans, or discontinued because of progressive disease or treatment-related adverse events (full analysis set). This study is registered with ClinicalTrials.gov, number NCT01848834, and is no longer enrolling patients; follow-up is ongoing. FINDINGS: Between May 14, 2013, and Dec 10, 2013, 115 patients were tissue pre-screened as part of a two-part consent process. 61 (53%) patients were PD-L1 positive, of whom 33 were enrolled in this study. All enrolled patients received at least one dose of pembrolizumab and were included in the safety analyses. 27 patients comprised the full analysis set and were deemed assessable for activity. Six patients were not assessable: three discontinued study drug because of a non-treatment-related adverse event before the first post-baseline scan, two withdrew before the first post-baseline scan, and one had no measurable disease at baseline. The most common treatment-related adverse events were fatigue (six [18%] of 33 patients) and peripheral oedema (4 [12%]). Five (15%) patients had 11 grade 3 treatment-related adverse events; no single event occurred in more than one patient. Three (9%) patients experienced five serious treatment-related adverse events. After median follow-up of 13 months (range 1-26, IQR 5-23), an overall response was achieved in seven (26% [95% CI 11-46]) of 27 assessable patients, with three (11% [2-29]) complete and four (15% [4-34]) partial responses. Of the four deaths that occurred during the study (cardiac arrest, pneumonia, sepsis, and subarachnoid haemorrhage), none were deemed treatment related. INTERPRETATION: Pembrolizumab showed anti-tumour activity and acceptable safety in patients with advanced urothelial cancer, supporting ongoing phase 2 and 3 studies of pembrolizumab in this population. FUNDING: Merck & Co., Inc.

Pembrolizumab for patients with PD-L1-positive advanced gastric cancer (KEYNOTE-012): a multicentre, open-label, phase 1b trial.

BACKGROUND: Expression of PD-L1 has been shown to be upregulated in some patients with gastric cancer. As part of the phase 1b KEYNOTE-012 study, we aimed to assess the safety and activity of the anti-PD-1 antibody pembrolizumab in patients with PD-L1-positive recurrent or metastatic adenocarcinoma of the stomach or gastro-oesophageal junction. METHODS: This study was a multicentre, open-label, phase 1b trial done at 13 cancer research centres in the USA, Israel, Japan, South Korea, and Taiwan. We enrolled patients with PD-L1-positive recurrent or metastatic adenocarcinoma of the stomach or gastro-oesophageal junction. Patients received intravenous pembrolizumab at 10 mg/kg once every 2 weeks for 24 months or until progression or unacceptable toxic effects occurred. Response was assessed every 8 weeks in accordance with Response Evaluation Criteria in Solid Tumors version 1.1. The primary objectives were safety in patients who received at least one dose of pembrolizumab and the proportion of patients achieving overall responses in patients who received at least one pembrolizumab dose and who either had a post-baseline scan or who discontinued therapy because of clinical disease progression or a treatment-related adverse event before the first post-baseline scan. The study is registered with ClinicalTrials.gov, number NCT01848834, and is ongoing but no longer enrolling patients. FINDINGS: From Oct 23, 2013, to May 5, 2014, 39 patients were enrolled. 36 were evaluable for response by central assessment. Eight (22%, 95% CI 10-39) patients were judged to have had an overall response at central review; all responses were partial. All 39 patients were included in the safety analyses. Five (13%) patients had a total of six grade 3 or 4 treatment-related adverse events, consisting of two cases of grade 3 fatigue, one case each of grade 3 pemphigoid, grade 3 hypothyroidism, and grade 3 peripheral sensory neuropathy, and one case of grade 4 pneumonitis. No treatment-related deaths occurred. INTERPRETATION: In this population of patients with recurrent or metastatic PD-L1-positive gastric cancer, pembrolizumab had a manageable toxicity profile and promising antitumour activity, warranting further study in phase 2 and 3 trials. FUNDING: Merck & Co.

Primary pituitary lymphoma: a histological, immunohistochemical, and ultrastructural study with literature review.

We report the case of a 62-year-old man with headache and left sixth cranial nerve palsy. A computerized tomography scan revealed an osteolytic process involving the sella turcica and clivus. A partial tumor resection was achieved via an endoscopic transsphenoidal approach. Morphologic investigation revealed a diffuse large B cell lymphoma involving pituitary parenchyma. No systemic disease was found upon staging. Primary pituitary lymphoma is extremely rare. An accurate histologic diagnosis is key to successful treatment and a favorable prognosis. The literature is reviewed.

Rectal gastrointestinal stromal tumor mimicking a primary prostatic lesion.

The interstitial cells of Cajal have been identified in locations beyond the gastrointestinal tract, including the prostate, uterus and bladder. Indeed, there are reports of primary gastrointestinal stromal tumor (GIST) arising from each of these sites. We report the case of a 72-year old male who presented with benign prostatic hypertrophy and was diagnosed on retropubic prostatectomy as having a GIST. While the initial clinical and radiologic impression was that of a primary prostatic GIST, subsequent imaging ultimately revealed a small rectal extension as the source of the lesion. The purpose of our report is to highlight the need to assiduously rule-out gastrointestinal sources of GIST prior to making the diagnosis of primary prostatic GIST.

Inhibition of poly(adenosine diphosphate-ribose) polymerase attenuates ventilator-induced lung injury.

BACKGROUND: Mechanical ventilation can induce organ injury associated with overwhelming inflammatory responses. Excessive activation of poly(adenosine diphosphate-ribose) polymerase enzyme after massive DNA damage may aggravate inflammatory responses. Therefore, the authors hypothesized that the pharmacologic inhibition of poly(adenosine diphosphate-ribose) polymerase by PJ-34 would attenuate ventilator-induced lung injury. METHODS: Anesthetized rats were subjected to intratracheal instillation of lipopolysaccharide at a dose of 6 mg/kg. The animals were then randomly assigned to receive mechanical ventilation at either low tidal volume (6 ml/kg) with 5 cm H2O positive end-expiratory pressure or high tidal volume (15 ml/kg) with zero positive end-expiratory pressure, in the presence and absence of intravenous administration of PJ-34. RESULTS: The high-tidal-volume ventilation resulted in an increase in poly(adenosine diphosphate-ribose) polymerase activity in the lung. The treatment with PJ-34 maintained a greater oxygenation and a lower airway plateau pressure than the vehicle control group. This was associated with a decreased level of interleukin 6, active plasminogen activator inhibitor 1 in the lung, attenuated leukocyte lung transmigration, and reduced pulmonary edema and apoptosis. The administration of PJ-34 also decreased the systemic levels of tumor necrosis factor alpha and interleukin 6, and attenuated the degree of apoptosis in the kidney. CONCLUSION: The pharmacologic inhibition of poly(adenosine diphosphate-ribose) polymerase reduces ventilator-induced lung injury and protects kidney function.

Parathyroid chief cell adenoma associated with massive chronic parathyroiditis in a woman with hyperparathyroidism.

We report here the case of a 43-year-old woman with hyperparathyroidism, parathyroid chief cell adenoma, and massive chronic parathyroiditis. The patient was diagnosed with breast cancer and received chemotherapy 3 years before parathyroidectomy. The question can be raised whether chemotherapeutic agents may damage parathyroid cells leading to loss of self-tolerance and autoimmune chronic parathyroiditis.

Flow cytometry in the differential diagnosis of lymphocyte-rich thymoma from precursor T-cell acute lymphoblastic leukemia/lymphoblastic lymphoma.

We compared the antigen expression profile of thymocytes in lymphocyte-rich thymoma with that of precursor T-cell acute lymphoblastic leukemia/lymphoblastic lymphoma (T-cell ALL/LBL) cells using 4-colorflow cytometry. In all 15 thymoma cases, the thymocytes demonstrated 3 distinct subpopulations. The least mature cells (double-negative) expressed low-density CD2 and CD5, high-density CD7, CD10, CD34, and heterogeneous CD4 and CD8. They had the lowest density CD45 expression and were surface CD3-. The immature cells (double-positive) expressed CD2, CD5, CD7, CD4, CD8, heterogeneous surface CD3, and intermediate-density CD45. They were CD10- and CD34-. The mature cells (single-positive) expressed CD2, surface CD3, CD5, CD7, and CD4 or CD8. The heterogeneous expression of surface CD3, CD4, and CD8 also created a characteristic smearing pattern for these antigens. In all 15 T-cell ALL/LBL cases, the lymphoblasts formed a tight cluster without discrete subpopulations or smearing pattern. Of 5 double-negative cases, 4 demonstrated loss of CD2, CD10, or CD34 expression. Of 7 double-positive cases, 5 showed complete loss of surface CD3, CD2, and/or CD5; 4 were CD10+; and 2 were CD34+. Of 3 single-positive cases, 2 showed loss of CD2 and/or aberrant expression of CD34. Analysis of antigen expression pattern, the presence or absence of T cell-associated antigen deletion, and the expression of CD10 and CD34 by 4-color flow cytometry can help differentiate thymoma from T-cell ALL/LBL.

Immunophenotypic analysis of anaplastic large cell lymphoma by flow cytometry.

We studied the antigen expression profiles of 19 anaplastic large cell lymphoma (ALCL) cases by multiparameter flow cytometry. The neoplastic cells expressed CD45, HLA-DR, and CD30 in all cases. At least 1 T cell-associated antigen was expressed in each case (CD2, 12/17 [71%]; CD4, 12/19 [63%]; CD3, 6/19 [32%]; CD7, 6/19 [32%]; CD5, 5/19 [26%]; CD8, 4/19 [21%]). CD25 was expressed in 14 (88%) of 16 cases. CD13 was expressed unexpectedly in 8 (47%) of 17 cases. One CD13+ ALCL also was positive for CD33 and 2 others for CD15, CD19, CD20, CD22, CD14, and CD36 were not expressed. Anaplastic lymphoma kinase protein was detected in about 33% (3/9) of ALCLs examined by flow cytometric immunophenotyping (FCI); expression was validated by immunohistochemical analysis. Of 19 ALCL cases, 12 were diagnosed solely based on FCI findings in conjunction with morphologic evaluation of body fluid (1 case), fine-needle aspirate (3 cases), or excisional biopsy specimen (8 cases). The diagnoses of the remaining 7 cases were suggested strongly by FCI and confirmed by immunohistochemical analysis. FCI is useful to aid in diagnosis of ALCL, particularly along with fine-needle aspiration evaluation. ALCL with aberrant expression of myeloid antigens should not be mistaken for extramedullary myeloid tumor.