Association of combined PD-L1 expression and tumour-infiltrating lymphocyte features with survival and treatment outcomes in patients with metastatic melanoma.

BACKGROUND: Recent advances obtained with immune checkpoint inhibitors (ICIs) targeting the programmed cell death-1 (PD-1) protein have significantly improved the outcome of patients with metastatic melanoma. The PD-L1 expression in tumour cells as detected by immunohistochemistry is a predictive biomarker in some solid tumours, but appears insufficient as prognostic or predictive factor of response to ICIs in metastatic melanomas. OBJECTIVES: We investigated whether the presence and the features of pretreatment CD8+ tumour-infiltrating T lymphocytes (TILs) could be a complementary prognostic or predictive biomarker in patients with metastatic melanoma. METHODS: In this retrospective study, we evaluated the association of PD-L1 expression ≥5% of tumour cells combined with TIL features (CD8, CD28, Ki67) with the overall survival (OS) among 51 patients treated with ICIs and 54 patients treated with other treatment options (non-ICIs). RESULTS: PD-L1 positivity was observed in 33% and 39% of primary melanomas and matched metastases, respectively, with, however, poor concordance between the primary and the matched metastatic site (κ = 0.283). No significant association was noted between PD-L1 expression and CD8+ TIL profile analysed as single markers and OS or response to immunotherapy. Instead, their combined analysis in primary melanoma samples showed that the PD-L1-/CD8+ status was significantly associated with prolonged OS in the whole population (P = 0.04) and in the subgroup treated with non-ICIs (P = 0.009). Conversely, the PD-L1+/CD8+ status was a good prognostic factor in patients treated with ICIs (P = 0.022), whereas was significantly associated with poor prognosis in patients treated with non-ICIs (P = 0.014). While the expression of CD28 was not related to outcome, the Ki67 expression was significantly associated with poor OS in the subgroup CD8+ TIL+/PD-L1- (P = 0.02). CONCLUSIONS: The pretreatment combination of PD-L1 expression with the level of CD8+ TILs could better assess OS and predict therapeutic response of patients with metastatic melanoma treated by either immunotherapy or other treatment regimens.

Comparative study of the PD-L1 status between surgically resected specimens and matched biopsies of NSCLC patients reveal major discordances: a potential issue for anti-PD-L1 therapeutic strategies.

BACKGROUND: High expression of programmed death ligand-1 (PD-L1) on tumor cells (TC) and/or on tumor-infiltrating immune cells (IC) is associated with a high response rate in patients with advanced nonsmall-cell lung cancer (NSCLC) treated with PD-L1 inhibitors. The use of a PD-L1 immunohistochemical (IHC) test in determining the responsiveness to immunotherapy has raised the question of the reliability and reproducibility of its evaluation in lung biopsies compared with corresponding resected surgical specimens. PATIENTS AND METHODS: PD-L1 expression in TC and IC was assessed in 160 patients with operable NSCLC on both whole surgical tissue sections and matched lung biopsies, by using a highly sensitive SP142 IHC assay. The specimens were scored as TC 0-3 and IC 0-3 based on increasing PD-L1 expression. RESULTS: PD-L1 expression was frequently discordant between surgical resected and matched biopsy specimens (the overall discordance rate = 48%; 95% confidence interval 4.64-13.24) and κ value was equal to 0.218 (poor agreement). In all cases, the biopsy specimens underestimated the PD-L1 status observed on the whole tissue sample. PD-L1-positive IC tumors were more common than PD-L1-positive TC tumors on resected specimens. The discrepancies were mainly related to the lack of a PD-L1-positive IC component in matched biopsies. CONCLUSIONS: Our results indicate relatively poor association of the PD-L1 expression in TC and IC between lung biopsies and corresponding resected tumors. Although these results need to be further validated in larger cohorts, they indicate that the daily routine evaluation of the PD-L1 expression in diagnostic biopsies can be misleading in defining the sensitivity to treatment with PD-L1 targeted therapy.

NF-kB2 induces senescence bypass in melanoma via a direct transcriptional activation of EZH2.

Enhancer of Zeste homologue 2 (EZH2) belongs to the polycomb repressive complex 2 and catalyzes the methylation of histone H3 lysine 27. These pivotal epigenetic marks are altered in many cancers, including melanoma, as a result of EZH2 overexpression. Here, we show that the non-canonical-NF-kB pathway accounts for most of the NF-kB activity in melanoma cells, in contrast to non-cancer cells. We identify the non-canonical-NF-kB pathway as a key regulator of EZH2 expression in melanoma. We show a striking correlation between NF-kB2 and EZH2 expression in human melanoma metastases. We demonstrate that inhibition of the non-canonical NF-kB pathway by targeting NF-kB2/p52 or the upstream kinase NIK restores the senescence program in melanoma cells through the decrease of EZH2. On the contrary, the overexpression of NF-kB2/p52 in normal human melanocytes prevents stress- and oncogene-induced senescence. Finally, we show in mouse models that the inhibition of the non-canonical NF-kB pathway restores senescence and induces a dramatic reduction in tumor growth compared with controls, thus providing potential drug targets for the re-induction of senescence in melanoma and other cancers where EZH2 is overexpressed.

ALK-gene rearrangement: a comparative analysis on circulating tumour cells and tumour tissue from patients with lung adenocarcinoma.

BACKGROUND: A subgroup of anaplastic lymphoma kinase (ALK)-rearranged lung tumours can respond to ALK inhibitors. Until now, the ALK status in circulating tumour cells (CTCs) isolated from patients with lung cancer has not been characterised. We assessed the ALK status in CTCs detected in patients with lung cancer and correlated the results to the ALK status defined in the corresponding tumour tissue. PATIENTS AND METHODS: A total of 87 patients with lung adenocarcinoma showing CTCs isolated using the isolation by size of epithelial tumour cell method were screened for their ALK status both in tumour samples and in CTCs. ALK break-apart fluorescence in situ hybridisation (FISH) and immunoreactivity analyses using an anti-ALK antibody (5A4 clone) were carried out on CTCs and compared with the results obtained in the corresponding tissue specimens. RESULTS: A total of five patients showed ALK-gene rearrangement and strong ALK protein expression in CTCs and in the corresponding tumour samples. Both ALK-FISH and ALK immunoreactivity analyses show negative results in CTCs and corresponding tumour samples for 82 patients. Conclusions We demonstrated that the ALK status can be determined in CTCs isolated from patients with lung cancer by immunocytochemistry and FISH analyses. These results favour non-invasive, ALK-gene status pre-screening on a routine basis on CTCs isolated from patients with lung cancer and open new avenues for real-time monitoring for adapted targeted therapy.