The male germ cell gene regulator CTCFL is functionally different from CTCF and binds CTCF-like consensus sites in a nucleosome composition-dependent manner.

RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are.BACKGROUND: CTCF is a highly conserved and essential zinc finger protein expressed in virtually all cell types. In conjunction with cohesin, it organizes chromatin into loops, thereby regulating gene expression and epigenetic events. The function of CTCFL or BORIS, the testis-specific paralog of CTCF, is less clear. RESULTS: Using immunohistochemistry on testis sections and fluorescence-based microscopy on intact live seminiferous tubules, we show that CTCFL is only transiently present during spermatogenesis, prior to the onset of meiosis, when the protein co-localizes in nuclei with ubiquitously expressed CTCF. CTCFL distribution overlaps completely with that of Stra8, a retinoic acid-inducible protein essential for the propagation of meiosis. We find that absence of CTCFL in mice causes sub-fertility because of a partially penetrant testicular atrophy. CTCFL deficiency affects the expression of a number of testis-specific genes, including Gal3st1 and Prss50. Combined, these data indicate that CTCFL has a unique role in spermatogenesis. Genome-wide RNA expression studies in ES cells expressing a V5- and GFP-tagged form of CTCFL show that genes that are downregulated in CTCFL-deficient testis are upregulated in ES cells. These data indicate that CTCFL is a male germ cell gene regulator. Furthermore, genome-wide DNA-binding analysis shows that CTCFL binds a consensus sequence that is very similar to that of CTCF. However, only ~3,700 out of the ~5,700 CTCFL- and ~31,000 CTCF-binding sites overlap. CTCFL binds promoters with loosely assembled nucleosomes, whereas CTCF favors consensus sites surrounded by phased nucleosomes. Finally, an ES cell-based rescue assay shows that CTCFL is functionally different from CTCF. CONCLUSIONS: Our data suggest that nucleosome composition specifies the genome-wide binding of CTCFL and CTCF. We propose that the transient expression of CTCFL in spermatogonia and preleptotene spermatocytes serves to occupy a subset of promoters and maintain the expression of male germ cell genes

International consensus guidelines for scoring the histopathological growth patterns of liver metastasis

BACKGROUND: Liver metastases present with distinct histopathological growth patterns (HGPs), including the desmoplastic, pushing and replacement HGPs and two rarer HGPs. The HGPs are defined owing to the distinct interface between the cancer cells and the adjacent normal liver parenchyma that is present in each pattern and can be scored from standard haematoxylin-and-eosin-stained (H&E) tissue sections. The current study provides consensus guidelines for scoring these HGPs. METHODS: Guidelines for defining the HGPs were established by a large international team. To assess the validity of these guidelines, 12 independent observers scored a set of 159 liver metastases and interobserver variability was measured. In an independent cohort of 374 patients with colorectal liver metastases (CRCLM), the impact of HGPs on overall survival after hepatectomy was determined. RESULTS: Good-to-excellent correlations (intraclass correlation coefficient >0.5) with the gold standard were obtained for the assessment of the replacement HGP and desmoplastic HGP. Overall survival was significantly superior in the desmoplastic HGP subgroup compared with the replacement or pushing HGP subgroup (P=0.006). CONCLUSIONS: The current guidelines allow for reproducible determination of liver metastasis HGPs. As HGPs impact overall survival after surgery for CRCLM, they may serve as a novel biomarker for individualised therapies

Blockade of LAG3 enhances responses of tumor-infiltrating T cells in mismatch repair-proficient liver meta

Purpose: Liver metastasis develops in >50% of patients with colorectal cancer (CRC), and is a leading cause of CRC-related mortality. We aimed to identify which inhibitory immune checkpoint pathways can be targeted to enhance functionality of intra-tumoral T-cells in mismatch repair-proficient liver metastases of colorectal cancer (LM-CRC). Methodology: Intra-tumoral expression of multiple inhibitory molecules was compared among mismatch repair-proficient LM-CRC, peritoneal metastases of colorectal cancer (PM-CRC) and primary CRC. Expression of inhibitory molecules was also analyzed on leukocytes isolated from paired resected metastatic liver tumors, tumor-free liver tissues, and blood of patients with mismatch repair-proficient LM-CRC. The effects of blocking inhibitory pathways on tumor-infiltrating T-cell responses were studied in ex vivo functional assays. Results: Mismatch repair-proficient LM-CRC showed higher expression of inhibitory receptors on intra-tumoral T-cells and contained higher proportions of CD8+ T-cells, dendritic cells and monocytes than mismatch repair-proficient primary CRC and/or PM-CRC. Inhibitory receptors LAG3, PD-1, TIM3 and CTLA4 were higher expressed on CD8+ T-cells, CD4+ T-helper and/or regulatory T-cells in LM-CRC tumors compared with tumor-free liver and blood. Antibody blockade of LAG3 or PD-L1 increased proliferation and effector cytokine production of intra-tumoral T-cells isolated from LM-CRC in response to both polyclonal and autologous tumor-specific stimulations. Higher LAG3 expression on intra-tumoral CD8+ T-cells associated with longer progression-free survival of LM-CRC patients. Conclusion: Mismatch repair-proficient LM-CRC may be more sensitive to immune checkpoint inhibitors than mismatch repair-proficient primary CRC. Blocking LAG3 enhances tumor-infiltrating T-cell responses of mismatch repair-proficient LM-CRC, and therefore may be a new promising immunotherapeutic target for LM-CRC

Follow-up strategy and survival for five common cancers: A meta-analysis

Background : This meta-analysis aimed to evaluate the effectiveness of intensive follow-up after curative intent treatment for five common solid tumours, in terms of survival and treatment of recurrences. Methods : A systematic literature search was conducted, identifying comparative studies on follow-up for colorectal, lung, breast, upper gastro-intestinal and prostate cancer. Outcomes of interest were overall survival (OS), cancer specific survival (CSS), and treatment of recurrences. Random effects meta-analyses were conducted, with particular focus on studies at low risk of bias. Results : Fourteen out of 63 studies were considered to be at low risk of bias (8 colorectal, 4 breast, 0 lung, 1 upper gastro-intestinal, 1 prostate). These studies showed no significant impact of intensive follow-up on OS (hazard ratio, 95% confidence interval) for colorectal (0.99; 0.92–1.06), breast 1.06 (0.92–1.23), upper gastro-intestinal (0.78; 0.51–1.19) and prostate cancer (1.00; 0.86–1.16). No impact on CSS (hazard ratio, 95% confidence interval) was found for colorectal cancer (0.94; 0.77–1.16). CSS was not reported for other cancer types. Intensive follow-up increased the rate of curative treatment (relative risk; 95% confidence interval) for colorectal cancer recurrences (1.30; 1.05–1.61), but not for upper gastro-intestinal cancer recurrences (0.92; 0.47–1.81). For the other cancer types, no data on treatment of recurrences was available in low risk studies. Conclusion : For colorectal and breast cancer, high quality studies do not suggest an impact of intensive follow-up strategies on survival. Colorectal cancer recurrences are more often treated locally after intensive follow-up. For other cancer types evaluated, limited high quality research on follow-up is available

Local tumour control after radiofrequency or microwave ablation for colorectal liver metastases in relation to histopathological growth patterns

BACKGROUND: Regrowth after ablation is common, but predictive factors for local control are scarce. This study investigates whether histopathological growth patterns (HGP) can be used as a predictive biomarker for local control after ablation of colorectal liver metastases (CRLM). METHODS: Patients who received simultaneous resection and ablation as first treatment for CRLM between 2000 and 2019 were considered eligible. HGPs were determined on resected CRLM according to international guidelines and were classified as desmoplastic or non-desmoplastic. As minimal inter-tumoural heterogeneity has been demonstrated, the HGP of resected and ablated CRLM were presumed to be identical. Local tumour progression (LTP) was assessed on postoperative surveillance imaging. Uni- and multivariable competing risk methods were used to compare LTP. RESULTS: In total 221 patients with 443 ablated tumours were analysed. A desmoplastic HGP was found in 60 (27.1%) patients who had a total of 159 (34.7%) ablated lesions. Five-year LTP [95%CI] was significantly higher for ablated CRLM with a presumed non-desmoplastic HGP (37% [30-43] vs 24% [17-32], Gray's-test p = 0.014). On multivariable analysis, a non-desmoplastic HGP (adjusted HR [95%CI]; 1.55 [1.03-2.35]) was independently associated with higher LTP rates after ablation. CONCLUSION: HGP is an independent predictor of local tumour progression following ablation of CRLM