Functional Engagement of the PD-1/PD-L1 Complex But Not PD-L1 Expression Is Highly Predictive of Patient Response to Immunotherapy in Non-Small-Cell Lung Cancer.

PURPOSE: In many cancers, the expression of immunomodulatory ligands leads to immunoevasion, as exemplified by the interaction of PD-L1 with PD-1 on tumor-infiltrating lymphocytes. Profound advances in cancer treatments have come with the advent of immunotherapies directed at blocking these immuno-suppressive ligand-receptor interactions. However, although there has been success in the use of these immune checkpoint interventions, correct patient stratification for these therapies has been challenging. MATERIALS AND METHODS: To address this issue of patient stratification, we have quantified the intercellular PD-1/PD-L1 interaction in formalin-fixed paraffin-embedded tumor samples from patients with non-small cell lung carcinoma, using a high-throughput automated quantitative imaging platform (quantitative functional proteomics [QF-Pro]). RESULTS: The multisite blinded analysis across a cohort of 188 immune checkpoint inhibitor-treated patients demonstrated the intra- and intertumoral heterogeneity of PD-1/PD-L1 immune checkpoint engagement and notably showed no correlation between the extent of PD-1/PD-L1 interaction and PD-L1 expression. Importantly, PD-L1 expression scores used clinically to stratify patients correlated poorly with overall survival; by contrast, patients showing a high PD-1/PD-L1 interaction had significantly better responses to anti-PD-1/PD-L1 treatments, as evidenced by increased overall survival. This relationship was particularly strong in the setting of first-line treatments. CONCLUSION: The functional readout of PD-1/PD-L1 interaction as a predictive biomarker for the stratification of patients with non-small-cell lung carcinoma, combined with PD-L1 expression, should significantly improve the response rates to immunotherapy. This would both capture patients excluded from checkpoint immunotherapy (high PD-1/PD-L1 interaction but low PD-L1 expression, 24% of patients) and additionally avoid treating patients who despite their high PD-L1 expression do not respond and suffer from side effects.

Ultrasound Tumor Size Assessment, Histology and Serum Enzyme Analysis in a Rat Model of Colorectal Liver Cancer.

During tumor development, tissue necrosis appears as a natural phenomenon directly associated with an increase in tumor size. The aim of this study was to assess the use of ultrasound (US) for predicting natural tumor necrosis in a rat liver implant model of colorectal cancer. To achieve this goal, we sought to establish a correlation between US-measured tumor volume, serum enzyme levels and histopathological findings, particularly those regarding necrosis phenomena in liver implants. Under US guidance, CC531 colorectal cancer cells were injected into the left liver lobe of WAG/RijHsd rats. Twenty-eight days after cell inoculation, tumor volume was measured by US, and rats were sacrificed to obtain samples of tumor tissue as well as blood serum. In hematoxylin and eosin-stained tumor samples, the percentage of tumor that was necrotic was estimated. The association between percentage tumor necrosis and US-measured tumor volume was assessed by univariate logistic regression analysis, and a linear regression equation was obtained. Serum enzyme levels did not differ significantly between tumor-bearing and tumor-free rats. Tumor implants appeared as well-defined hyper-echoic regions with a mean volume of 0.61 ± 0.39 mL and tumor necrosis percentage of 8.6 ± 7.7%. Linear regression analysis revealed a very strong relationship (Pearson correlation coefficient r = 0.911) between US-measured tumor volume and tumor necrosis percentage; the regression equation was tumor necrosis percentage = 21 × US-measured tumor volume (in mL) - 3.1. The study found US to be a useful tool in animal-based trials. Tumors inside the liver (ranging in volume from 0.24-1.37 mL) can be observed by US, and moreover, US-measured tumor volume on day 28 can be used to estimate tumor necrosis occurring as the natural evolution of tumor implants.

Antitumor magnetic hyperthermia induced by RGD-functionalized Fe3O4 nanoparticles, in an experimental model of colorectal liver metastases.

This work reports important advances in the study of magnetic nanoparticles (MNPs) related to their application in different research fields such as magnetic hyperthermia. Nanotherapy based on targeted nanoparticles could become an attractive alternative to conventional oncologic treatments as it allows a local heating in tumoral surroundings without damage to healthy tissue. RGD-peptide-conjugated MNPs have been designed to specifically target αVß3 receptor-expressing cancer cells, being bound the RGD peptides by "click chemistry" due to its selectivity and applicability. The thermal decomposition of iron metallo-organic precursors yield homogeneous Fe3O4 nanoparticles that have been properly functionalized with RGD peptides, and the preparation of magnetic fluids has been achieved. The nanoparticles were characterized by transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), electron magnetic resonance (EMR) spectroscopy and magnetic hyperthermia. The nanoparticles present superparamagnetic behavior with very high magnetization values, which yield hyperthermia values above 500 W/g for magnetic fluids. These fluids have been administrated to rats, but instead of injecting MNP fluid directly into liver tumors, intravascular administration of MNPs in animals with induced colorectal tumors has been performed. Afterwards the animals were exposed to an alternating magnetic field in order to achieve hyperthermia. The evolution of an in vivo model has been described, resulting in a significant reduction in tumor viability.

Study of the intra-arterial distribution of Fe3O4 nanoparticles in a model of colorectal neoplasm induced in rat liver by MRI and spectrometry.

PURPOSE: To evaluate, in an experimental model, the reliability of MRI for determining whether a higher iron concentration was obtained in tumor tissue than in normal liver parenchyma after intra-arterial administration of Fe3O4 lipophilic nanoparticles. MATERIALS AND METHODS: WAG/RijCrl rats were inoculated in the left hepatic lobe with 25,000 syngeneic CC-531 colon adenocarcinoma cells, after which they were randomized into two groups: control (CG) and infused (IG). After confirming tumor induction, the IG rats received intra-arterial suspensions of Fe3O4 nanoparticles (2.6 mg) in Lipiodol® (0.15 mL). To calculate the iron concentration, [Fe], in the tumor and liver tissues of both groups of rats, measurements of signal intensity from the tumors, healthy liver tissue, and paravertebral muscles were made on a 1.5T MRI system in gradient-echo DP* and T2*-weighted sequences. In addition, samples were collected to quantify the [Fe] by inductively coupled plasma-mass spectrometry (ICP-MS), as well as for histological analysis. Statistical analysis was performed with non-parametric tests, and Bland-Altman plots were produced; P values <0.05 were considered significant. RESULTS: In the CG rats (n = 23), the mean [Fe] values estimated by MRI and ICP-MS were 13.2 µmol·g⁻¹ and 5.9 µmol·g⁻¹, respectively, in the tumors, and 19.0 µmol ·g⁻¹ and 11.7 µmol·g⁻¹, respectively, in the hepatic tissue. In the IG rats (n = 19), the values obtained by MRI and ICP-MS were 148.9 µmol·g⁻¹ and 9.4 µmol · g⁻¹, respectively, in the tumors, and 115.3 µmol·g⁻¹ and 11.6 µmol·g⁻¹, respectively, in the healthy liver tissue. The IG results revealed a clear disagreement between MRI and ICP-MS. In the comparative analysis between the groups regarding the [Fe] values obtained by ICP-MS, significant differences were found for the tumor samples (P < 0.001), but not for the hepatic tissue (P = 0.92). Under microscopy, scattered intravascular deposits of nanoparticles were observed, especially in the tumors. CONCLUSION: ICP-MS demonstrated significant uptake of exogenous iron in tumor tissue. MRI was useful for quantifying the [Fe] in the different tissues in the CG animals, but not in the IG animals. Although the irregular distribution of nanoparticles caused an important bias in the measurements obtained by MRI, the relative increase in iron content inside the tumor was suggested.

Neurotecoma celular. Presentación de dos casos / Cellular neurothekeoma. Report of two cases

El neurotecoma celular es una tumoración cutáneabenigna poco frecuente de histogénesis incierta, que ocurrefundamentalmente en la parte superior del cuerpo de niñosy adultos jóvenes, con predominio femenino. Clásicamentese considera que los neurotecomas (variantes mixoide, celulary mixta) forman parte de un espectro de tumores consupuesto origen en la vaina nerviosa. Sin embargo, la faltade diferenciación neurosustentacular convincente tanto enel neurotecoma celular como en el mixto ha cuestionadoeste concepto, y numerosos autores afirman que se trata detumores diferentes que justifican una clasificación separada.Se presentan dos casos de neurotecoma celular, en unvarón de 24 años y en una niña de 9 años, con tumoracionesasintomáticas en el hombro derecho y en la rodilla izquierdarespectivamente. Histológicamente, ambos casos secaracterizan por una proliferación en la dermis reticular decélulas fusiformes y/o epitelioides dispuestas en nidos yfascículos, rodeados por un estroma colágeno denso. Unode los casos muestra importante atipia citológica y unpatrón marcadamente plexiforme. Inmunohistoquímicamente,ambos casos son positivos para vimentina, CD68,CD10, factor XIIIa y actina músculo-liso. En uno de loscasos también hay inmunorreactividad para enolasa neuronalespecífica. El resto de los marcadores realizados sonnegativos, entre ellos la proteína S-100. Los hallazgosinmunohistoquímicos sugieren diferenciación fibrohistiocitaria,lo que probablemente justifica la separación del neurotecomacelular del neurotecoma mixoide. En cuanto alneurotecoma mixto, éste probablemente representa unavariante mixoide del neurotecoma celular (AU)

Cellular neurothekeoma is a rare benign cutaneous neoplasmof uncertain histogenesis arising usually on the upperbody of children and young adults, with a female predominance.Neurothekeomas (myxoid, cellular and mixedvariants) are classically regarded as forming part of a spectrumof tumors of putative nerve sheath origin. The lack ofconvincing evidence of neurosustentacular differentiation incellular and mixed variants, however, has challenged thisconcept, and numerous authors state that they are differenttumors that warrant a separate classification. This is thereport of two cases of cellular neurothekeoma, in a 24-yearoldman and a 9-year-old girl, with asymptomatic tumorsoccurring on the right shoulder and left knee respectively.Histologically, both cases are characterized by a proliferationof spindle and/or epithelioid cells involving reticulardermis, arranged in fascicles and nests surrounded by scleroticcollagen. One of the two cases show significant cytologicatypia and a notably plexiform pattern. Immunohistochemically,both cases are positive for vimentin, CD68,CD10, factor XIIIa and smoth muscle actin. In one of thetwo cases there is also immunoreactivity for neuron-specificenolase. The remainder of immunomarkers are negative,S-100 protein included. The immunohistochemical findingssuggest fibrohistiocytic differentiation, so it probablywarrants the separation of cellular neurothekeoma frommyxoid neurothekeoma. In respect to the mixed neurothekeoma,this probably represents a myxoid variant of cellularneurothekeoma (AU)