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. 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. 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. 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.

As targeted molecular therapies and immuno-oncology have become pivotal in the management of patients with lung cancer, the essential requirement for high throughput analyses and clinical validation of biomarkers has become even more intense, with response rates maintained in the 20%–30% range. Moreover, the list of treatment alternatives, including combination therapies, is rapidly evolving. The molecular profiling and specific tumor-associated immune contexture may be predictive of response or resistance to these therapeutic strategies. Multiplexed immunohistochemistry is an effective and proficient approach to simultaneously identify specific proteins or molecular abnormalities, to determine the spatial distribution and activation state of immune cells, as well as the presence of immunoactive molecular expression. This method is highly advantageous for investigating immune evasion mechanisms and discovering potential biomarkers to assess mechanisms of action and to predict response to a given treatment. This review provides views on the current technological status and evidence for clinical applications of multiplexing and how it could be applied to optimize clinical management of patients with lung cancer.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT • Hand–foot syndrome (HFS) is a limiting toxicity of the widely used fluorouracil (5FU) prodrug capecitabine.• The pharmacological origin of HFS has not been elucidated.• The expression of capecitabine‐metabolizing enzymes thymidine phosphorylase (TP, activating pathway) and dihydropyrimidine dehydrogenase (DPD, catabolic pathway) in the skin of the palm (target tissue for HFS) is unknown. WHAT THIS STUDY ADDS • This pilot study, conducted in healthy volunteers, clearly demonstrated that TP expression is significantly greater in the palm compared with the lower back (control area).• This suggests TP‐facilitated enhanced production of 5FU in the palm that could explain the occurrence of HFS.• This result may support strategies to prevent HFS.AIMS: The oral fluoropyrimidine prodrug capecitabine is widely used in oncology. Capecitabine was designed to generate 5FU via the thymidine phosphorylase (TP) enzyme, preferentially expressed in tumoral tissues. Hand–foot syndrome (HFS) is a limiting toxicity of capecitabine. A pilot study on healthy volunteers was conducted in order to test the hypothesis that the occurrence of HFS could be related to tissue‐specific expression of drug‐metabolizing enzymes in the skin of the palm and sole. To this end, the expression of TP (activating pathway), dihydropyrimidine dehydrogenase (DPD, catabolic pathway) and cell proliferation (Ki67) were measured in the skin of the palm (target tissue for HFS) and of the lower back (control area).METHODS: Two paired 4‐mm diameter punch biopsy specimens (palm and back) were taken in 12 healthy volunteers. Immunohistochemical analyses were performed on frozen tissues.RESULTS: Proliferation rate (Ki67 staining) was significantly higher in epidermal basal cells of the palm compared with the back (P = 0.008). Also, TP and DPD expression were significantly greater in the palm relative to the back (P = 0.039 and 0.012, respectively). TP and Ki67 expression were positively and significantly correlated in the palm.CONCLUSIONS: The high proliferation rate of epidermal basal cells in the palm could make them more sensitive to the local action of cytotoxic drugs. TP‐facilitated local production of 5FU in the palm during capecitabine treatment could explain the occurrence of HFS. This observation may support future strategies to limit the occurrence of HFS during capecitabine therapy.

The molecular mechanism responsible for the antitumor activity of histone deacetylase inhibitors (HDACi) remains elusive. As HDACi have been described to alter miRNA expression, the aim of this study was to characterize HDACi-induced miRNAs and to determine their functional importance in the induction of cell death alone or in combination with other cancer drugs. Two HDACi, trichostatin A and vorinostat, induced miR-129-5p overexpression, histone acetylation and cell death in BCPAP, TPC-1, 8505C, and CAL62 cell lines and in primary cultures of papillary thyroid cancer (PTC) cells. In addition, miR-129-5p alone was sufficient to induce cell death and knockdown experiments showed that expression of this miRNA was required for HDACi-induced cell death. Moreover, miR-129-5p accentuated the anti-proliferative effects of other cancer drugs such as etoposide or human α-lactalbumin made lethal for tumor cells (HAMLET). Taken together, our data show that miR-129-5p is involved in the antitumor activity of HDACi and highlight a miRNA-driven cell death mechanism.

Uveal melanoma (UM) is the most common malignant intraocular tumour in the adult population. It is a rare cancer with an incidence of nearly five cases per million inhabitants per year, which develops from the uncontrolled proliferation of melanocytes in the choroid (≈90%), ciliary body (≈6%) or iris (≈4%). Patients initially present either with symptoms like blurred vision or photopsia, or without symptoms, with the tumour being detected in routine eye exams. Over the course of the disease, metastases, which are initially dormant, develop in nearly 50% of patients, preferentially in the liver. Despite decades of intensive research, the only approach proven to mildly control disease spread are early treatments directed to ablate liver metastases, such as surgical excision or chemoembolization. However, most patients have a limited life expectancy once metastases are detected, since there are limited therapeutic approaches for the metastatic disease, including immunotherapy, which unlike in cutaneous melanoma, has been mostly ineffective for UM patients. Therefore, in order to offer the best care possible to these patients, there is an urgent need to find robust models that can accurately predict the prognosis of UM, as well as therapeutic strategies that effectively block and/or limit the spread of the metastatic disease. Here, we initially summarized the current knowledge about UM by compiling the most relevant epidemiological, clinical, pathological and molecular data. Then, we revisited the most important prognostic factors currently used for the evaluation and follow-up of primary UM cases. Afterwards, we addressed emerging prognostic biomarkers in UM, by comprehensively reviewing gene signatures, immunohistochemistry-based markers and proteomic markers resulting from research studies conducted over the past three years. Finally, we discussed the current hurdles in the field and anticipated the future challenges and novel avenues of research in UM.

Background: The aim of this study was to compare the detection of BRAF ^V600E by immunohistochemistry (IHC) using a mutation-specific antibody with molecular biology methods for evaluation of papillary thyroid carcinoma (PTC) patients. Patients and methods: This study concerned 198 consecutive conventional PTC patients, of which the majority were women (133/198; 67%), with a mean age of 56 years (range 19–79 years). BRAF mutation analysis was performed using DNA-based (direct sequencing, pyrosequencing, and SNaPshot) and IHC (VE1 antibody) methods. The sensitivity and specificity of IHC for BRAF ^V600E was compared with the molecular biology data. Results: A BRAF mutational result was obtained in 194 cases. A BRAF ^V600E mutation was detected in 153/194 (79%) cases of PTC when using at least one molecular method, and in 151/194 (78%) cases with IHC. No false positive results were noted using IHC to detect the BRAF ^V600E mutation. Besides this mutation, other rare BRAF mutations ( BRAF ^V600K and BRAF ^K601E ), used as negative controls, were consistently negative with IHC. The sensitivity and specificity of IHC for the detection of this mutation were 98.7% and 100% respectively. The IHC test demonstrated excellent performance at a level equivalent to two DNA-based counterparts (pyrosequencing and SNaPshot). Failure to achieve a result was more frequent with the direct sequencing method than with the three other methods. Conclusion: IHC using the VE1 antibody is a specific and sensitive method for the detection of the BRAF ^V600E mutation in PTC. IHC may be an alternative to molecular biology approaches for the routine detection of this mutation in PTC patients.