Improved survival of gastric cancer with tumour Epstein–Barr virus positivity: an international pooled analysis

About 9% of gastric carcinomas have Epstein–Barr virus (EBV) in the tumour cells, but it is unclear whether viral presence influences clinical progression. We therefore examined a large multicentre case series for the association of tumour EBV status with survival after gastric cancer diagnosis, accounting for surgical stage and other prognostic factors

PROLINE DEHYDROGENASE EXPRESSION, REGULATION AND FUNCTION IN NON-SMALL CELL LUNG CARCINOMA

Non-Small Cell Lung Cancer (NSCLC) is one of the most frequent and deadliest cancers and comprises two main histotypes, adenocarcinoma (ADC) and squamocellular carcinoma (SCC). Identification of markers to better define the diagnosis, prognosis and therapeutic options of NSCLC is needed. We investigated if proline dehydrogenase (PRODH), a mitochondrial flavoenzyme catalyzing the key step in proline degradation, and involved in the regulation of cell survival, autophagy and apoptosis, may be one such marker. Materials and methods We characterized PRODH expression in NSCLC by immunohistochemistry and qPCR and tested if there was correlation between expression of PRODH and clinical features of the tumors or expression of other markers. We aimed to test what cellular processes are influenced by PRODH in lung ADC cell lines. To do so, we tested the effect of regulating PRODH expression in ADC tumour cell lines on their behaviour, by performing a panel of phenotypic assays. Results and discussion We found PRODH immunostaining in the majority (70%) of lung ADCs. Patients with PRODH positive tumors had better overall survival than those with negative tumors. Protein staining was paralleled by high transcript levels, suggesting transcriptional regulation. In A549 and H1437 ADC cell lines, ectopic modulation of PRODH expression suggested that PRODH favoured survival of these ADC cells, whereas in NCI-H1650 cells overexpression led to a decrease in clonogenic ability. In the latter cell line, PRODH expressing clones also showed a reduced 3D growth in soft agar compared to control clones. Conclusion Our immunohistochemistry data support a possible use of PRODH immunostaining as a prognostic marker. However, further research is necessary to 1) identify molecular interactors that can influence the outcome and 2) to better define the downstream processes activated by PRODH in lung cancer cells

Histotype-based prognostic classification of gastric cancer

AIM: To test the efficiency of a recently proposed histotype-based grading system in a consecutive series of gastric cancers

EBV+ and MSI Gastric Cancers Harbor High PD-L1/PD-1 Expression and High CD8+ Intratumoral Lymphocytes

Both EBV+ and MSI gastric cancers (GCs) have high lymphoid infiltration which is rare in MSS/EBV− cancers. PD-L1/PD-1 interaction leads to a down-regulated immune response and it is one of the most promising targets for gastric cancer immunotherapy. PD-L1/PD-1 and CD8 expression were immunohistochemically investigated in a series of 169 FFPE GCs, including 33 EBV+, 59 MSI and 77 MSS/EBV− cases. PD-L1 membrane immunoreactivity in more than 5% of tumor cells was present in 31/169 GCs and was associated with high levels of CD8 intraepithelial lymphocytes (TILs; p < 0.001). PD-L1+ cases were mainly poorly differentiated (71%), intestinal type (85%) and high lymphoid response (HLR; 90%) tumors. PD-L1 expression was only present in EBV⁺ (46%), MSI (24%) and rare MSS/EBV− (3%) GCs with high CD8+ TILs (p < 0.001). Despite being associated with a better prognosis both in the whole series (p < 0.05) and in the MSI subset, PD-L1 is not an independent prognostic factor. PD-L1 gene amplification was detected in 3/17 cases, including 2/7 EBV+ and 1/8 MSI GC. PD-1⁺ TILs were significantly higher in EBV⁺ than MSI and MSS/EBV− cases. PD-L1/PD-1 pathway is selectively activated in HLR GCs and could be considered an emerging therapeutic target, particularly for EBV and MSI GCs

CIITA-related block of HLA class II expression, upregulation of HLA class I, and heterogeneous expression of immune checkpoints in hepatocarcinomas: implications for new therapeutic approaches

Hepatocellular carcinoma (HCC) is the second cause of death for cancer worldwide, justifying the urgent need for novel therapeutic approaches. Immunotherapeutic strategies based on triggering and/or rescuing tumor antigen-specific T cells may be promising particularly if combined together. As preliminary step toward this goal, we have investigated the expression of antigen presenting molecules (HLA class I and class II) and immune checkpoints (PD-1 and PD-L1) in 43 HCC samples from distinct patients and in HCC cell lines. While normal hepatocytes did not express HLA class I and II, HCC cells strongly upregulated HLA class I while remaining negative for HLA class II. The absence of HLA class II expression in HCC cell lines correlated with lack of expression of the HLA class II transactivator, CIITA, which could not be rescued even after interferon-gamma treatment. This was due to high methylation levels of interferon-gamma-sensitive CIITA promoter IV strongly suggesting a biologically relevant developmental silencing of HLA-II expression in liver cell lineage. HCC tumor tissues showed a variable degree of leukocyte infiltration. Infiltrating lymphocytes expressed PD-1, while PD-L1 was expressed in cells with monocyte-macrophage morphology mostly localized at the tumor margin, but not in tumor cells. De novo expression of HLA class I, instrumental for presenting tumor antigens to cytotoxic T lymphocytes, and the correct characterization of the cells expressing checkpoint inhibitors in the tumor tissue should be the ground for setting novel strategies of combined approaches of immunotherapy in HCC based on tumor peptide vaccines and anti-checkpoint inhibitor antibodies

Targeted gene sequencing of Lynch syndrome\u2013related and sporadic endometrial carcinomas

About one-third of endometrial carcinomas (ECs), mainly of endometrioid histology, harbor the mismatch repair (MMR) defects and microsatellite instability (MSI). Among these, ECs arising in women with Lynch syndrome (LS) account for a large proportion. To date, no somatic genetic analyses have been published comparing LS-ECs with sporadic ECs. In this work, we examined the mutational profiles of a well-characterized series of sporadic and LS-related ECs, performing exonic targeted sequencing of 16 genes mainly involved in MSI ECs. Next-generation sequencing analysis was performed in 35 ECs on the MiSeq platform (Illumina, San Diego, CA), and the mutational profile was analyzed integrating molecular and immunohistochemical data. PTEN, ARID1A, and ARID2 were the most frequently mutated genes regardless of MSI status or family history. MSI ECs showed a higher mutational load than MMR-proficient cases, exhibiting an MMR-deficient mutational signature. Among MSI tumors, LS-related and sporadic ECs exhibited similar mutational profiles, with MSH2 as the most commonly mutated gene. KRAS mutations seemed to be more common in sporadic MSI ECs than in LS-related ECs even if further studies are needed to confirm this finding. MMR-deficient ECs carried a higher mutational load and an excess of C>T transitions compared with MMR-proficient ECs, suggesting that the use of a small gene panel may be adequate to highlight significant differences between these 2 groups. An integrated analysis of genetic and epigenetic features of LS-related and sporadic ECs provides useful insights into disease biology and diagnostic classification of these tumors

Microsatellite analysis of sporadic and hereditary gynaecological cancer in routine diagnostics

Microsatellite instability (MSI) testing is tricky in gynaecological cancers (GC). Thus, we aimed to describe the instability patterns to improve MSI test interpretation in sporadic and hereditary GCs. Ninety-five cases, including uterine and ovarian cancers, with known genetic and immunohistochemical (IHC) features, were analysed for MSI by a mononucleotide repeats pentaplex (MRP). We identified 13 ambiguous cases that did not fully meet MSI criteria ('borderline' cases, B-MSI), which were mainly represented by MSH2/MSH6-deficient and Lynch syndrome cases. Also, we evaluated nine additional loci of candidate MSI markers that did not improve the detection of MSI cases, but might be useful for discordant or borderline samples. In conclusion, although MSI and IHC test are highly concordant, a subset of ambiguous MSI cases deserves a careful interpretation in particular when MSH2/MSH6 are involved. RPL22 and SRPR testing may be useful to integrate MRP panel for the analysis of critical cases