Association of PD-1/PD-L axis expression with cytolytic activity, mutational load, and prognosis in melanoma and other solid tumors.

Programmed cell death protein-1 (PD-1)/programmed death ligand-1 (PD-L1) checkpoint blockade has led to remarkable and durable objective responses in a number of different tumor types. A better understanding of factors associated with the PD-1/PD-L axis expression is desirable, as it informs their potential role as prognostic and predictive biomarkers and may suggest rational treatment combinations. In the current study, we analyzed PD-L1, PD-L2, PD-1, and cytolytic activity (CYT) expression, as well as mutational density from melanoma and eight other solid tumor types using The Cancer Genome Atlas database. We found that in some tumor types, PD-L2 expression is more closely linked to Th1/IFNG expression and PD-1 and CD8 signaling than PD-L1 In contrast, mutational load was not correlated with a Th1/IFNG gene signature in any tumor type. PD-L1, PD-L2, PD-1, CYT expression, and mutational density are all positive prognostic features in melanoma, and conditional inference modeling revealed PD-1/CYT expression (i.e., an inflamed tumor microenvironment) as the most impactful feature, followed by mutational density. This study elucidates the highly interdependent nature of these parameters, and also indicates that future biomarkers for anti-PD-1/PD-L1 will benefit from tumor-type-specific, integrated, mRNA, protein, and genomic approaches.

Melanoma subtypes demonstrate distinct PD-L1 expression profiles.

PD-L1 expression in the tumor immune microenvironment is recognized as both a prognostic and predictive biomarker in patients with cutaneous melanoma, a finding closely related to its adaptive (IFN-γ-mediated) mechanism of expression. Approximately 35% of cutaneous melanomas express PD-L1, however, the expression patterns, levels, and prevalence in rarer melanoma subtypes are not well described. We performed immunohistochemistry for PD-L1 and CD8 on 200 formalin-fixed paraffin-embedded specimens from patients with acral (n=16), mucosal (n=36), uveal (n=103), and chronic sun-damaged (CSD) (n=45) melanomas (24 lentigo maligna, 13 'mixed' desmoplastic, and 8 'pure' desmoplastic melanomas). CD8+ tumor-infiltrating lymphocyte (TIL) densities were characterized as mild, moderate, or severe, and their geographic association with PD-L1 expression was evaluated. Discrete lymphoid aggregates, the presence of a spindle cell morphology, and the relationship of these features with PD-L1 expression were assessed. PD-L1 expression was observed in 31% of acral melanomas, 44% of mucosal melanomas, 10% of uveal melanomas, and 62% of CSD melanomas (P<0.0001). Compared to our previously characterized cohort of cutaneous melanomas, the proportion of PD-L1(+) tumors was lower in uveal (P=0.0002) and higher in CSD (P=0.0073) melanomas, while PD-L1 expression in the acral and mucosal subtypes was on par. PD-L1 expression in all subtypes correlated with a moderate-severe grade of CD8+ TIL (all, P<0.003), supporting an adaptive mechanism of expression induced during the host antitumor response. The tumor microenvironments observed in CSD melanomas segregated by whether they were the pure desmoplastic subtype, which showed lower levels of PD-L1 expression when compared to other CSD melanomas (P=0.047). The presence of lymphoid aggregates was not associated with the level of PD-L1 expression, while PD-L1(+) cases with spindle cell morphology demonstrated higher levels of PD-L1 than those with a nested phenotype (P<0.0001). Our findings may underpin the reported clinical response rates for anti-PD-1 monotherapy, which vary by subtype.

Efficacy and Tolerability of a Novel Biopsy Device for Removing Benign Epidermal Skin Lesions.

BACKGROUND: The shave biopsy using a razor with an open blade is the current standard of care for sampling superficial skin lesions. OBJECTIVE: To enhance safety, the authors developed a novel biopsy device with a closed blade design for removing the epidermal layer of skin and evaluated against the open razor blade for tolerability, scarring, and accuracy in histological diagnosis. MATERIALS AND METHODS: Shave biopsies were performed using the novel device or razor blade on benign epidermal skin lesions in 10 patients on comparable body parts. Digital photography, colorimetry, scar scale evaluations, and questionnaires were used to evaluate the efficacy and tolerability of the devices. RESULTS: For all patients, accurate histological diagnoses were made regardless of device type. No statistically significant differences were detected between the novel device and razor blade in terms of scar scale assessments, colorimetry, and questionnaire responses. Both patients and the participating dermatologist reported satisfaction with the safety and performance of the novel device. No injuries to the provider occurred with either instrument. CONCLUSION: The rotating sphere biopsy device is a potential alternative to the razor blade with comparable tolerability, scarring, and accuracy in histological diagnoses, offering improved safety for patients and health care providers.

Basal cell carcinoma: PD-L1/PD-1 checkpoint expression and tumor regression after PD-1 blockade.

Monoclonal antibodies that block immune regulatory proteins such as programmed death-1 (PD-1) have demonstrated remarkable efficacy in controlling the growth of multiple tumor types. Unresectable or metastatic basal cell carcinoma, however, has largely gone untested. Because PD-Ligand-1 (PD-L1) expression in other tumor types has been associated with response to anti-PD-1, we investigated the expression of PD-L1 and its association with PD-1 expression in the basal cell carcinoma tumor microenvironment. Among 40 basal cell carcinoma specimens, 9/40 (22%) demonstrated PD-L1 expression on tumor cells, and 33/40 (82%) demonstrated PD-L1 expression on tumor-infiltrating lymphocytes and associated macrophages. PD-L1 was observed in close geographic association to PD-1+ tumor infiltrating lymphocytes. Additionally, we present, here, the first report of an objective anti-tumor response to pembrolizumab (anti-PD-1) in a patient with metastatic PD-L1 (+) basal cell carcinoma, whose disease had previously progressed through hedgehog pathway-directed therapy. The patient remains in a partial response 14 months after initiation of therapy. Taken together, our findings provide a rationale for testing anti-PD-1 therapy in patients with advanced basal cell carcinoma, either as initial treatment or after acquired resistance to hedgehog pathway inhibition.

Association of HIV Status With Local Immune Response to Anal Squamous Cell Carcinoma: Implications for Immunotherapy.

IMPORTANCE: The programmed cell death protein 1 (PD-1) and programmed death-ligand 1 (PD-L1) pathway play an important immunosuppressive role in cancer and chronic viral infection, and have been effectively targeted in cancer therapy. Anal squamous cell carcinoma (SCC) is associated with both human papillomavirus and HIV infection. To date, patients with HIV have been excluded from most trials of immune checkpoint blocking agents, such as anti-PD-1 and anti-PD-L1, because it was assumed that their antitumor immunity was compromised compared with immunocompetent patients. OBJECTIVE: To compare the local tumor immune microenvironment (TME) in anal SCCs from HIV-positive and HIV-negative patients. DESIGN, SETTING, AND PARTICIPANTS: Anal SCC tumor specimens derived from the AIDS and Cancer Specimen Resource (National Cancer Institute) and Johns Hopkins Hospital included specimens. Tumors were subjected to immunohistochemical analysis for immune checkpoints (PD-L1, PD-1, LAG-3) and immune cell (IC) subsets (CD3, CD4, CD8, CD68). Expression profiling for immune-related genes was performed on select HIV-positive and HIV-negative cases in PD-L1+ tumor areas associated with ICs. MAIN OUTCOMES AND MEASURES: Programmed death-ligand 1 expression on tumor cells and ICs, PD-L1 patterns (adaptive vs constitutive), degree of IC infiltration, quantified densities of IC subsets, and gene expression profiles in anal SCCs from HIV-positive vs HIV-negative patients. RESULTS: Approximately half of 40 tumor specimens from 23 HIV-positive and 17 HIV-negative patients (29 men and 11 women; mean [SD] age, 51 [9.9] years) demonstrated tumor cell PD-L1 expression, regardless of HIV status. Median IC densities were not significantly decreased in HIV-associated tumors for any cellular subset studied. Both adaptive (IC-associated) and constitutive PD-L1 expression patterns were observed. Immune cell PD-L1 expression correlated with increasing intensity of IC infiltration (r = 0.52; 95% CI, 0.26-0.78; P < .001) and with CD8+ T-cell density (r = 0.35; 95% CI, 0.11-0.59; P = .03). Gene expression profiling revealed comparable levels of IFNG in the TME of both HIV-positive and HIV-negative patients. A significant increase in IL18 expression levels was observed in HIV-associated anal SCCs (fold change, 12.69; P < .001). CONCLUSIONS AND RELEVANCE: HIV status does not correlate with the degree or composition of IC infiltration or PD-L1 expression in anal SCC. These findings demonstrate an immune-reactive TME in anal SCCs from HIV-positive patients and support clinical investigations of PD-1/PD-L1 checkpoint blockade in anal SCC, irrespective of patient HIV status.

PD-L1 Expression in Melanoma: A Quantitative Immunohistochemical Antibody Comparison.

Purpose: PD-L1 expression in the pretreatment tumor microenvironment enriches for response to anti-PD-1/PD-L1 therapies. The purpose of this study was to quantitatively compare the performance of five monoclonal anti-PD-L1 antibodies used in recent landmark publications.Experimental Design: PD-L1 IHC was performed on 34 formalin-fixed paraffin-embedded archival melanoma samples using the 5H1, SP142, 28-8, 22C3, and SP263 clones. The percentage of total cells (including melanocytes and immune cells) demonstrating cell surface PD-L1 staining, as well as intensity measurements/H-scores, were assessed for each melanoma specimen using a computer-assisted platform. Staining properties were compared between antibodies.Results: Strong correlations were observed between the percentage of PD-L1(+) cells across all clones studied (R2 = 0.81-0.96). When present, discordant results were attributable to geographic heterogeneity of the melanoma tissue section rather than differences in PD-L1 antibody staining characteristics. PD-L1 intensity/H-scores strongly correlated with percentage of PD-L1(+) cells (R2 > 0.78, all clones).Conclusions: The 5H1, SP142, 28-8, 22C3, and SP263 clones all demonstrated similar performance characteristics when used in a standardized IHC assay on melanoma specimens. Reported differences in PD-L1 IHC assays using these antibodies are thus most likely due to assay characteristics beyond the antibody itself. Our findings also argue against the inclusion of an intensity/H-score in chromogenic PD-L1 IHC assays. Clin Cancer Res; 23(16); 4938-44. ©2017 AACR.

Cutaneous Eruptions in Patients Receiving Immune Checkpoint Blockade: Clinicopathologic Analysis of the Nonlichenoid Histologic Pattern.

Cutaneous eruptions are among the most common immune-related adverse events (irAEs) associated with anti-programmed cell death protein 1/programmed cell death ligand 1 therapy, and are often clinically and histologically characterized as lichenoid. Nonlichenoid patterns may also occur and are likely to be encountered by surgical pathologists, given the increasing clinical use of these agents. The purpose of this study is to describe the histopathologic features of nonlichenoid cutaneous irAEs from patients receiving anti-programmed cell death protein 1/programmed cell death ligand 1 therapies for a variety of underlying advanced malignancies. Sixteen patients with 17 biopsied eruptions were included from 2 academic institutions with extensive experience administering and monitoring responses to immune checkpoint blockade as well as treating the potential side effects. Eruptions occurred a median of 10 days (range, 1 d to 11.4 mo) after treatment initiation. Nearly half of specimens demonstrated either a psoriasiform/spongiotic or an urticarial-type reaction pattern on histologic review. Patterns consistent with Grover disease, bullous pemphigoid, and granulomatous dermatitis were also observed. Nearly two-thirds of patients required systemic corticosteroids for treatment of the cutaneous irAE, and 19% of patients discontinued immunotherapy due to their skin eruptions. 75% of patients showed an objective antitumor response. The diverse array of nonlichenoid cutaneous irAE presented here should reflect and inform the scope of histologic patterns encountered by the practicing surgical pathologist. Such eruptions are seen in patients with a variety of underlying tumor types, many of whom ultimately demonstrate a favorable response to immune checkpoint blockade.