High Expression of miR-34a Associated with Less Aggressive Cancer Biology but Not with Survival in Breast Cancer

MicroRNA-34 Family in Cancers: Role, Mechanism, and Therapeutic Potential

MicroRNA (miRNA) are small noncoding RNAs that play vital roles in post-transcriptional gene regulation by inhibiting mRNA translation or promoting mRNA degradation. The dysregulation of miRNA has been implicated in numerous human diseases, including cancers. miR-34 family members (miR-34s), including miR-34a, miR-34b, and miR-34c, have emerged as the most extensively studied tumor-suppressive miRNAs. In this comprehensive review, we aim to provide an overview of the major signaling pathways and gene networks regulated by miR-34s in various cancers and highlight the critical tumor suppressor role of miR-34s. Furthermore, we will discuss the potential of using miR-34 mimics as a novel therapeutic approach against cancer, while also addressing the challenges associated with their development and delivery. It is anticipated that gaining a deeper understanding of the functions and mechanisms of miR-34s in cancer will greatly contribute to the development of effective miR-34-based cancer therapeutics.

Metastasis Inhibition

Cancer metastasis is a common biological phenomenon observed in malignant tumors that can lead to death in affected individuals [...].

Recent Clinical Advances on Long Non-Coding RNAs in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a more aggressive type of breast cancer due to its heterogeneity and complex molecular mechanisms. TNBC has a high risk for metastasis, and it is difficult to manage clinical conditions of the patients. Various investigations are being conducted to overcome these challenges using RNA, DNA, and proteins for early diagnosis and treatment. Recently, long non-coding RNAs (lncRNAs) have emerged as a novel target to treat the multistep process of TNBC. LncRNAs regulate epigenetic expression levels, cell proliferation and apoptosis, and tumour invasiveness and metastasis. Thus, lncRNA-based early diagnosis and treatment options could be helpful, especially for patients with severe TNBC. lncRNAs are expressed in a highly specific manner in cells and tissues and are involved in TNBC progression and development. lncRNAs could be used as sensitive and specific targets for diagnosis, treatment, and monitoring of patients with TNBC. Therefore, the exploration of novel diagnostic and prognostic biomarkers is of extreme importance. Here, we discuss the molecular advances on lncRNA regulation of TNBC and lncRNA-based early diagnosis, treatment, and drug resistance.

High miR-99b expression is associated with cell proliferation and worse patient outcomes in breast cancer

Although miR-99b is a known suppressive microRNA (miRNA) in several cancers, its role in breast cancer has not been elucidated. In this study, we examined the clinical relevance of miR-99b expression in breast cancer. We analyzed miRNA and mRNA expression and their relationships with clinical parameters in 1,961 breast cancer samples from two independent large cohorts, the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) and The Cancer Genome Atlas (TCGA). Several algorithms, including gene set enrichment analysis (GSEA) and xCell, have been used to investigate biological functions and the tumor microenvironment. High miR-99b expression significantly enriched the mTORC1 signaling gene set in breast cancer (NES = 1.63, FDR = 0.03, and NES = 1.58, FDR = 0.10, in METABRIC and TCGA, respectively). No other mechanisms, including the epithelial mesenchymal transition, NFκB, and TGF-β signaling, were consistently enriched in both cohorts. MiR-99b-high breast cancer was associated with high homologous recombination deficiencies, intratumor heterogeneity, and high rates of mutation and neoantigens. In agreement, miR-99b-high breast cancer was associated with increased cell proliferation, correlating with Nottingham histological grade, and significant enrichment of E2F targets, G2/M checkpoint, and mitotic spindle gene sets consistently in both cohorts (P = 0.01, P < 0.001). High miR-99b levels were also associated with low stromal cell fractions in the tumor microenvironment, including adipocytes, keratinocytes, and lymphatic endothelial cells (P < 0.001). However, in both cohorts, miR-99b expression was not associated with significant infiltration of immune cells, except dendritic cells (P = 0.006, 0.020). Finally, in both cohorts, breast cancer with high miR-99b expression was significantly associated with worse disease-free survival (DSS) and overall survival (OS), particularly in estrogen receptor (ER)-positive/human epidermal growth factor (HER)2-negative breast cancer (DSS hazard ratio (HR) 1.29, 95% confidence interval (CI) 1.10-1.51, P < 0.001 in the METABRIC cohort and HR 1.82, 95% CI 1.12-2.98, P = 0.017 in the TCGA cohort). In conclusion, breast cancer with high miR-99b expression was significantly associated with mTORC1 signaling, cell proliferation, and decreased patient survival, particularly in the ER-positive/HER2-negative subtype.

Low adipocyte hepatocellular carcinoma is associated with aggressive cancer biology and with worse survival

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related death worldwide, and non-alcoholic fatty liver disease is strongly associated with its development. To explore the role of adipocytes in HCC, we investigated intratumoral adipocytes, also known as cancer-associated adipocytes (CAA). Based on our prior breast cancer findings, we hypothesized that low intratumoral adipocytes would be associated with aggressive cancer biology, worse tumor microenvironment (TME), and clinical outcomes. The Cancer Genome Atlas (TCGA) was used and validated by the Gene Expression Omnibus (GEO) cohort. xCell algorithm was used to quantify intratumoral adipocytes and top 90% were defined as adipocyte high (AH) and bottom 10% as adipocyte low (AL). We found that AL-HCC was significantly associated with worse disease-free survival (DFS), disease-specific survival (DSS), and overall survival (OS). AL-HCC were higher-grade, had high MKI67 expression, enriched cell proliferation-related gene sets, and had increased altered fraction, aneuploidy, and homologous recombination defects. Also, anti-cancer immune cells, CD8, Th1, and M1 cells, as well as pro-cancer Th2 cells were increased in AL-HCC. Micro-RNAs miR-122 (associated with cholesterol metabolism) and miR-885 (associated with liver pathologies) were significantly increased in the AL TME. In conclusion, we found that AL-HCC has worse patient outcomes and is biologically more aggressive with enhanced cell proliferation. Our findings take initial steps to clarify the role of adipocytes in HCC.

An immune-inflamed tumor microenvironment as defined by CD8 score is associated with favorable oncologic outcomes in hepatocellular carcinoma independent of measures of tumor mutational burden

Despite low mutational burden, immune checkpoint inhibitors have demonstrated promising results in a significant minority of hepatocellular carcinoma (HCC) patients with advanced disease. We hypothesized that HCC patients with higher levels of CD8+ T cell infiltration reflect an immune-inflamed cohort which has improved oncologic outcomes. 355 HCC patients with clinical and transcriptome data in the Cancer Genome Atlas (TCGA) and 151 HCC patients from cohort GSE7624 were analyzed. xCell computational algorithm was used to analyze immune cell infiltration in these patients. Each cohort was divided into high and low expression by the highest 2 terciles value. Gene Set Enrichment Analysis was performed to identify enriched gene sets. High CD8 score associated with improved overall survival in both cohorts (both P < 0.05). High score correlates with early BCLC stage (P = 0.035) but not AJCC stage. High CD8 also correlated with increased IFN-γ response (p = 0.038), lymphocyte infiltration (P < 0.001), and leukocyte fraction (P < 0.001). It was associated with increased polyclonality of T cell (P < 0.001) and B cell response (P = 0.017). High CD8 score correlated with increased cytolytic activity score (P < 0.001) and expression of multiple immune checkpoints including PD-1, PD-L1, CTLA-4 and Lag3 (all P < 0.001). There was no correlation to tumor mutational burden and neoantigens. GSEA demonstrated upregulation of several gene sets involved in inflammatory response and IFN-γ response. In conclusion, HCC patients with high CD8 score demonstrated favorable oncologic outcomes, which may be due to immune-mediated tumor cell attack. Furthermore, CD8 score may be a potentially useful biomarker to select patients for immune checkpoint inhibition.

Response to neoadjuvant chemotherapy in breast cancer: do microRNAs matter?

BACKGROUND

Conventionally, breast cancer (BC) prognosis and prediction of response to therapy are based on TNM staging, histological and molecular subtype, as well as genetic alterations. The role of various epigenetic factors has been elucidated in carcinogenesis. However, it is still unknown to what extent miRNAs affect the response to neoadjuvant chemotherapy (NACT). This pilot study is focused on evaluating the role of miR-34a, miR-124a, miR-155, miR-137 and miR-373 in response to NACT.

METHODS

That was a prospective study enrolling 34 patients with histologically confirmed BC of II-III stages. The median age of patients was 53 (47-59.8) years old, 70.6% of whom were HR-positive. MiRs levels were measured in the primary tumor before and after NACT. The response to therapy was assessed after surgery using the Miller-Payne scoring system. To establish the role of miRs in modulating response to NACT the Cox model was applied for analysis.

RESULTS

BC demonstrated a great variability of miRs expression before and after NACT with no strong links to tumor stage and molecular subtype. Only miR-124a and miR-373 demonstrated differential expression between malignant and normal breast tissues before and after therapy though these distinctions did not impact response to NACT. Besides miR-124a and miR-137 levels after NACT were found to be dependent on HR status. While miR-124a levels increased (p = 0.021) in the tumor tissue, the expression of miR-137 was downregulated (p = 0.041) after NACT in HR positive BC.

CONCLUSIONS

The study revealed differences in miR-124a and miR-373 expression after NACT in primary BC tissues. Although miRs levels did not impact the response to NACT, we found miR-124a and miR-137 levels to be related to hormonal sensitivity of BC.

MicroRNA-34a Promotes Ischemia-Induced Cardiomyocytes Apoptosis through Targeting Notch1

Myocardial apoptosis occurs during myocardial ischemia. This study aimed to determine the effect of microRNA-34a (miR-34a) in ischemia-induced myocardial apoptosis. Mainly, SD rats were subjected to myocardial ischemia by ligaturing the left anterior descending branch of coronary artery. After rats had myocardial infarction, HE staining and TUNEL staining confirmed a significant increase in apoptosis. The expression of miR-34a was noticeably upregulated, while the expression of Notch1 was downregulated. An increase in caspase-3 and a decrease in Bcl-2/Bax ratio were observed in myocardium. Similar results were observed in the in vitro model of cardiomyocyte ischemia and anoxia of this study. When rat cardiomyocytes were administered with serum starvation and microaerophilic system, apoptosis-related proteins were significantly increased. However, transfecting the miR-34a inhibitor into the cardiomyocyte before the serum starvation and hypoxia treatment could increase the ratio of Bcl-2/Bax and downregulate the expression of caspase-3, as well as prevent cardiomyocytes from apoptosis. As opposed to the abovementioned points, the upregulation of miR-34a expression by transfecting miR-34a mimics induced Notch1 reduce and apoptosis-related proteins increase apparently, while upregulation of Notch1 could stimulate apoptosis attributed to miR-34a. Mechanistically, we demonstrated that Notch1 is a direct target of miR-34a. In conclusion, our current results suggested that miR-34a significantly stimulates ischemia-induced cardiomyocytes apoptosis by targeting Notch1.

Intratumoral density of regulatory T cells is a predictor of host immune response and chemotherapy response in colorectal cancer

Regulatory T cells (Tregs) are a subset of CD4+ T lymphocytes known to dampen the host immune response against cancer cells. Within the tumor microenvironment, Tregs are potent facilitators of immune tolerance, and a higher proportion of Tregs compared to cytotoxic T cells predicts a worse outcome in most solid tumors. We studied the association between Treg density, and cancer biology and clinical outcome in colorectal cancer (CRC). We used xCell to estimate intratumoral Tregs in total of 898 CRC patients in the Cancer Genome Atlas (TCGA) and GCE39582 cohorts. High-Treg CRCs enriched immune response-related gene sets; inflammatory response, IFN-γ and IFN-α response, IL2/IL6 signaling, and allograft rejection, and had significantly high infiltration of CD8, CD4, M1 and M2 macrophage, and dendritic cells in both cohorts. While high-Treg CRCs enriched multiple pro-cancer signaling pathways compared to low-Treg CRCs, such as Epithelial Mesenchymal Transition, K-ras, Hypoxia, TGF-β, TNF-α, and angiogenesis, Treg infiltration was surprisingly associated with earlier CRC stage in TCGA. Notably, in two separate cohorts a higher proportion of Tregs predicted an improved response to chemotherapy. In the GSE28702 cohort, metastatic CRCs with more Tregs showed a significantly better response to mFOLFOX6 versus low-Treg CRC metastases (88.9% response vs. 16.7%, P<0.001). In the GSE72970 cohort, high-Treg CRCs were found to have a 68.8% response to FOLFOX/FOLFIRI without bevacizumab, compared to 44% response in the low-Treg CRCs. Additionally, high-Treg CRCs were associated with increased expression of immune checkpoint molecules PD-L1/PD-L2, CTLA4, TIGIT and BTLA, implying susceptibility to immunotherapy. We also found that CRCs with higher proportions of Tregs were associated with lower amounts of three microorganisms in the tumor: Lachnoclostridium, flavivirus, and Ornithobacterium. In conclusion, we show that amount of Treg in the tumor is a predictor of host immune response and chemotherapy response in CRC.

Intratumoral lymphatic endothelial cell infiltration reflecting lymphangiogenesis is counterbalanced by immune responses and better cancer biology in the breast cancer tumor microenvironment

Lymphangiogenesis, the generation of new lymphatic vessels from existing ones, results from the dynamic interactions of lymphatic endothelial cells and the tumor microenvironment (TME). It is well known that lymphangiogenesis occurs during the initial stage of metastasis in various types of malignant tumors. However, it is currently not used as a biomarker partially because gold standard method to quantify it is labor and cost intensive. We hypothesized that the quantity of intratumoral lymphatic endothelial cells (iLECs) in the TME is an indicator of lymphangiogenesis and a predictor of metastatic potential and overall survival in breast cancer. We analyzed a total of 4145 breast cancer patients from the Cancer Genome Atlas (TCGA) and GSE96058 by quantifying their iLECs using the xCell algorithm, and correlated these scores with patient survival, tumor grade, and cancer stage. We also assessed various pro- and anti-cancer gene sets for each tumor to characterize tumor behavior and aggressiveness. As we expected, high-iLEC breast cancer demonstrated enriched lymphoangiogenesis and angiogenesis gene sets and was associated with increased expressions of related genes. Also enriched were inflammatory response and immune response-related gene sets; IL2/STAT5 pathway, IL6/JAK/STAT3 pathway, TNFα pathway, allograft rejection, and complement as well as cancer stemness related gene sets like Notch signaling, Hedgehog signaling, epithelial mesenchymal transition, and Wnt beta-catenin signaling. Tumors with high-iLEC showed higher proportions of stromal cells and fewer anti-cancer immune cells. On the other hand, iLEC score did not correlate with patient survival or lymph node metastasis. Surprisingly, breast cancers with fewer iLECs demonstrated enriched E2F Targets, G2M Checkpoint, MYC Targets v1, and MTORC1 signaling which are cancer cell proliferation-related gene sets and exhibited an abundance of pro-cancer immune cells. The amount of iLEC correlated inversely with Ki67 expression and histological grade, which is in agreement that low-iLEC breast cancer was associated with enhanced cancer cell proliferation. In conclusion, while iLECs can be used as a surrogate for lymphangiogenesis in breast cancer, low-iLEC tumors also exhibit features which correspond to aggressive tumor biology, which may explain why the amount of iLECs was not associated with patient survival in our cohorts.

Low RUFY3 expression level is associated with lymph node metastasis in older women with invasive breast cancer

PURPOSE

Sentinel lymph node biopsy is omitted in older women (≥ 70 years old) with clinical lymph node (LN)-negative hormone receptor-positive breast cancer as it does not influence adjuvant treatment decision-making. However, older women are heterogeneous in frailty while the chance of recurrence increase with improving longevity. Therefore, a biomarker that identifies LN metastasis may facilitate treatment decision-making. RUFY3 is associated with cancer progression. We evaluated RUFY3 expression level as a biomarker for LN-positive breast cancer in older women.

METHODS

Clinical and transcriptomic data of breast cancer patients were obtained from the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC, n = 1903) and The Cancer Genome Atlas (TCGA, n = 1046) Pan-cancer study cohorts.

RESULTS

A total of 510 (METABRIC) and 211 (TCGA) older women were identified. LN-positive breast cancer, which represented 51.4% (METABRIC) and 48.4% (TCGA), demonstrated worse disease-free, disease-specific, and overall survival. RUFY3 levels were significantly lower in LN-positive tumors regardless of age. The area under the curve for the receiver operator characteristic (AUC-ROC) curves showed RUFY3-predicted LN metastasis. Low RUFY3 enriched oxidative phosphorylation, DNA repair, MYC targets, unfolded protein response, and mtorc1 signaling gene sets, was associated with T helper type 1 cell infiltration, and with intratumor heterogeneity and fraction altered. Low RUFY3 expression was associated with LN-positive breast cancer and with worse disease-specific survival among older women.

CONCLUSION

Older women with breast cancers who had low expression level of RUFY3 were more frequently diagnosed with LN-positive tumors, which translated into worse prognosis.

MIEAP, a p53-downstream gene, is associated with suppression of breast cancer cell proliferation and better survival

Mitochondria-eating protein (MIEAP; also known as SPATA18), a p53-downstream gene, is involved in mitochondrial quality control (MQC). Enforced MIEAP expression induces caspase-dependent cell death in vitro, and impairment of the p53/MIEAP-regulated MQC pathway is frequently observed in breast cancer (BC), resulting in poor disease-free survival (DFS). To investigate the clinical significance of MIEAP in BC, we identified 2,980 patients from two global, large-scale primary BC cohorts: the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC; n=1,904) and the Cancer Genome Atlas (TCGA; n=1,076). We divided patients in each cohort into high and low groups based on median gene expression levels and analyzed the association between MIEAP expression and clinical outcomes. Compared with normal tumors, MIEAP expression was significantly downregulated in all patients with p53-mutant BC regardless of subtype. MIEAP expression was negatively correlated with KI67 expression. Gene set enrichment analysis demonstrated that cell cycle- and proliferation-associated gene sets were significantly enriched in MIEAP-low tumors compared to MIEAP-high tumors. Patients with MIEAP-high luminal subtype were associated with significantly longer DFS than those with MIEAP-low luminal tumors in both cohorts, whereas significantly longer overall survival was observed only in the METABRIC cohort, which has roughly double the number of samples. These results indicated that the mechanistic role of MIEAP is clinically relevant in the two independent cohorts. This is the first study to use large cohorts to demonstrate the association between MIEAP expression and survival in patients with luminal subtype BC.

Low intratumoral genetic neutrophil-to-lymphocyte ratio (NLR) is associated with favorable tumor immune microenvironment and with survival in triple negative breast cancer (TNBC)

Patients with triple negative breast cancer (TNBC) have a poor prognosis. A novel prognostic biomarker may guide management by appropriately selecting patients for particular treatments. Peripheral blood neutrophil-to-lymphocyte ratio (NLR) was reported to associate with cancer progression, thus we hypothesized that intratumor genetic NLR will reflect tumor immune microenvironment (TIME) and breast cancer biology. The intratumoral genetic NLR previously defined as the ratio of CD66b (CEACAM8) and CD8 (CD8A) gene expressions was utilized to analyze total of 2,994 patients from METABRIC, TCGA, GSE21094, GSE22358, GSE25088, GSE32646, and GSE2603 cohorts. Intratumoral genetic NLR did not correlate with cancer stage nor clinical parameters of cancer cell proliferation such as Nottingham histological grade or MKI67 expression levels in neither the METABRIC or TCGA cohorts. Intratumoral genetic NLR-high breast cancer was not associated with pathologic complete response (pCR) after neoadjuvant chemotherapy in 5 independent cohorts with different regimens. Despite these results, intratumoral genetic NLR-high TNBC demonstrated worse disease-free, disease-specific, and overall survival. Intratumoral genetic NLR-low TNBC enriched multiple immune-related gene sets, was associated with higher favorable immune-related scores and with a favorable TIME, whereas no gene sets enriched to NLR-high TNBC. In conclusion, intratumoral genetic NLR-low TNBC was associated with favorable TIME and with better survival.

Sphingosine 1-phosphate (S1P) produced by sphingosine kinase 1 (SphK1) and exported via ABCC1 is related to hepatocellular carcinoma (HCC) progression

Sphingosine-1-Phosphate (S1P) is produced by Sphingosine Kinase 1 (SphK1) in the cell and is transported out of the cells by ABCC1 transporter. S1P induces inflammation, angiogenesis and modulates tumor immune microenvironment (TIME) in autocrine and paracrine manner. We hypothesized that high S1P export is associated with hepatocellular carcinoma (HCC) progression and worse survival. Transcriptome linked with clinical data were obtained from a total of 533 patients from TCGA (The Cancer Genome Atlas)-HCC (n = 350), GSE6764 (n = 75), and GSE89377 (n = 108) cohorts. Both SphK1 and ABCC1 were expressed higher in aggressive HCC than normal liver or cirrhosis and correlated with MKi67 expression. High S1P export by high expression of both SphK1 and ABCC1 enriched gene sets related with cell proliferation (E2F targets, G2M checkpoint, MYC targets), inflammation (Inflammatory response, TNFα, IL6), angiogenesis, metastasis (TGF-β, epithelial-mesenchymal transition), and immune response (allograft rejection, complement, interferon-gamma) in gene set enrichment analysis. High S1P export was associated with elevation of HGF, HSP90AA1, TRAF2, and AKR1B10. It was also associated with high intratumor heterogeneity, leucocyte fraction, macrophage regulation and lymphocyte infiltration, as well as T helper type2 cells, macrophages, dendritic cells, CD4⁺ T memory activated cells, B-cells and cytolytic activity score in TIME. High S1P export was associated with significantly worse disease specific survival (P = 0.034) and overall survival (P = 0.004) compared to low S1P export group. In conclusion, simultaneous high expression of SphK1 and ABCC1 that reflect S1P export is associated with enhancement of both HCC progression and immune response. Given that S1P export was also associated with worse survival, we cannot help but speculate that pro-cancer pathways activated by S1P may overwhelm the anti-cancer immune response mediated by S1P.

Increased intratumor heterogeneity, angiogenesis and epithelial to mesenchymal transition pathways in metaplastic breast cancer

Metaplastic breast cancer (MBC) constitutes a rare but unique histologic entity with poor prognosis. We hypothesized that MBC possesses unique genetic profile and tumor immune microenvironment. MBC cases were identified from a total of 10827 breast cancer entries in the Cancer Genome Atlas Data Set (TCGA) and the AACR-GENIE (Genomics Evidence Neoplasia Information Exchange) cohorts. Tumor infiltrated immune cells were estimated by xCell. Baseline clinical characteristics were compared, and gene set enrichment analysis (GSEA) was performed. MBC comprised 0.66% of the cohorts (1.2% of TCGA and 0.6% of GENIE). MBC cases were predominantly triple-negative (TNBC) (8 (61.5%) vs 151 (14.4%), P<0.001), and high Nottingham histological grade (8 (61.5%) vs 222 (21.1%), P=0.02) compared to non-MBC in the TCGA cohort. Increased infiltration of M1 macrophages (P=0.012), dendritic cells (P<0.001) and eosinophils (P=0.036) was noted in the MBC cohort however there was no difference in cytolytic activity (P=0.806), CD4 memory (P=0.297) or CD8 T-cells (P=0.864). Tumor mutation burden was lower in the MBC compared to the non-MBC, median: 0.4 vs 1.6/Mb in the TCGA-TNBC cohort (P=0.67) and 3.0 vs 4.0/Mb (P=0.1) in the GENIE-cohort. MBC had increased intratumor heterogeneity (P<0.001), macrophage regulation (P=0.008) and TGF-beta response (P<0.001). Disease-specific survival was decreased in MBC (P=0.018). Angiogenesis and epithelial-to-mesenchymal transition pathways were enriched in triple-negative MBC by GSEA (P=0.004 and P<0.001, respectively). Our results suggest that high intratumor heterogeneity, enriched angiogenesis and EMT pathway expression represent possible mechanisms leading to worse disease-specific survival found in metaplastic breast cancer.

Increased apoptosis is associated with robust immune cell infiltration and cytolytic activity in breast cancer

Tumor infiltrating immune cells plays a critical role in cancer progression. Apoptosis is an autonomous cell death that counteracts tumor growth. To this end, we hypothesized that increased apoptosis in breast cancer is associated with immune cell killing. Apoptosis score of MSigDB Hallmark collection was used to analyze METABRIC cohort (n=1904) and TCGA (n=1069) as validation cohort. High apoptosis tumors enriched cancer promoting signaling pathways; hypoxia, KRAS, TGF-β, PI3K signaling, and was associated with low MKI67 expression and less cell proliferation gene sets, less homologous recombination defects, and less altered fraction. High apoptosis tumors also enriched angiogenesis and high infiltration of vascular endothelial cells, pericytes and stromal cells and significantly enriched inflammation and immune response-related gene sets and high infiltration of CD8, CD4 memory, dendritic cells, M1 and M2 macrophages and significant elevation of cytolytic activity and immune checkpoint molecules, consistently in both cohorts. In conclusion, breast cancer patients with high apoptosis are associated with angiogenesis, immune response, high immune cell infiltration and cytolytic activity. To the best of our knowledge, this is the first study to utilize in silico translational approach to demonstrate the clinical relevance of apoptosis in breast cancer patients in large cohorts.

Low expression of miR-29a is associated with aggressive biology and worse survival in gastric cancer

Advanced gastric cancer (GC) is one of the most lethal cancer types, thus a better understanding of its biology in patients is urgently needed. MicroRNA (miR)-29a is a known tumor suppressive miR that is related to metastasis, but its clinical relevance in GC remains ambiguous. Here, using a large GC patient cohort we hypothesized that low expression of miR-29a in GC is associated with aggressive cancer biology and worse survival. We demonstrated that low miR-29a GC enriched cell proliferation, apoptosis, metastasis, and angiogenesis related gene sets, as well as the higher expression of related genes. Low miR-29a GC was associated with less anti-cancer immune cell infiltration as well as immune related scoring. Low miR-29a GC demonstrated a worse overall survival (OS) as well as disease specific survival (DSS) compared with high expressing miR-29a GC. Notably, low miR-29a expression was the only factor, other than residual tumor status, to be an independent prognostic biomarker of worse OS and DSS. In conclusion, low miR-29a GC was associated with aggressive cancer biology and worse OS as well as DSS. Additionally, low expression of miR-29a was an independent prognostic biomarker of OS and DSS in gastric cancer patients.

Low expression of miR-195 is associated with cell proliferation, glycolysis and poor survival in estrogen receptor (ER)-positive but not in triple negative breast cancer

MiR-195 is a tumor suppressive microRNA in breast cancer. Its clinical relevance remains debatable as it has only been studied via in vitro experiments or small cohort studies. We analyzed a total of 2,038 patients in the TCGA and METABRIC cohorts to assess whether low miR-195 expressing tumors are associated with aggressive cancer characteristics and poor prognostic outcomes. The median cutoff of miR-195 expression was used to split the groups into miR-195 high and low groups. Low miR-19 expressing tumors demonstrated high cell proliferating features by enriching the gene sets associated with cell proliferation, MKI67 expression and pathological grade. One-third of the top target miR-195 genes were related to cell proliferation. Low miR-195 expressing tumors were associated with both pro-cancerous and anti-cancerous immune cells. Low miR-195 expressing tumors were associated with enhanced glycolysis and poor survival in ER-positive tumors, but not other subtypes of breast cancer. In conclusion, low expression of miR-195 in ER-positive breast cancer was associated with enhanced cancer cell proliferation, glycolysis, and worse overall survival.

Urine as a Source of Liquid Biopsy for Cancer

Simple Summary

Tissue biopsy is essential for diagnosis and characterization of a tumor. Recently circulating tumor cells and other tumor-derived nucleic acid can be detected from blood, which is called liquid biopsy. Now this concept has been expanded to many other body fluids including urine. Urine is the least invasive method to obtain a liquid biopsy and can be done anywhere, which allows longitudinal repeated sampling. Here, we review the latest update on urine liquid biopsy in urological and non-urological cancers.

Abstract

Tissue biopsy is the gold standard for diagnosis and morphological and immunohistochemical analyses to characterize cancer. However, tissue biopsy usually requires an invasive procedure, and it can be challenging depending on the condition of the patient and the location of the tumor. Even liquid biopsy analysis of body fluids such as blood, saliva, gastric juice, sweat, tears and cerebrospinal fluid may require invasive procedures to obtain samples. Liquid biopsy can be applied to circulating tumor cells (CTCs) or nucleic acids (NAs) in blood. Recently, urine has gained popularity due to its less invasive sampling, ability to easily repeat samples, and ability to follow tumor evolution in real-time, making it a powerful tool for diagnosis and treatment monitoring in cancer patients. With the development and advancements in extraction methods of urinary substances, urinary NAs have been found to be closely related to carcinogenesis, metastasis, and therapeutic response, not only in urological cancers but also in non-urological cancers. This review mainly highlights the components of urine liquid biopsy and their utility and limitations in oncology, especially in non-urological cancers.

Enhanced Thermogenesis in Triple-Negative Breast Cancer Is Associated with Pro-Tumor Immune Microenvironment

Mild cold stress induced by housing mice with a 4T1 triple-negative breast cancer (TNBC) cell implantation model at 22 °C increases tumor growth rate with a pro-tumorigenic immune microenvironment (lower CD8 ⁺T cells, higher myeloid-derived suppressor cells (MDSCs) and regulatory T-cells (Tregs)). Since cold stress also activates thermogenesis, we hypothesized that enhanced thermogenesis is associated with more aggressive cancer biology and unfavorable tumor microenvironment (TME) in TNBC patients. A total of 6479 breast cancer patients from METABRIC, TCGA, GSE96058, GSE20194, and GSE25066 cohorts were analyzed using Kyoto Encyclopedia of Genes and Genomes (KEGG) thermogenesis score. High-thermogenesis TNBC was associated with a trend towards worse survival and with angiogenesis, adipogenesis, and fatty acid metabolism pathways. On the other hand, low-thermogenesis TNBC enriched most of the hallmark cell-proliferation-related gene sets (i.e., mitotic spindle, E2F targets, G2M checkpoint, MYC targets), as well as immune-related gene sets (i.e., IFN-α and IFN-γ response). Favorable cytotoxic T-cell-attracting chemokines CCL5, CXCL9, CXCL10, and CXCL11 were lower; while the MDSC- and Treg-attracting chemokine CXCL12 was higher. There were higher M2 but lower M1 macrophages and Tregs. In conclusion, high-thermogenesis TNBC is associated with pro-tumor immune microenvironment and may serve as biomarker for testing strategies to overcome this immunosuppression.

Angiogenesis is associated with an attenuated tumor microenvironment, aggressive biology, and worse survival in gastric cancer patients

Angiogenesis is a cornerstone of cancer as it allows tumors to receive oxygen and nutrients. A high level of angiogenesis within a tumor may therefore be indicative of its aggressiveness. In this study, we examined this hypothesis in gastric cancer. Gene set variation analysis was used to measure the level of angiogenesis in tumors in 1,348 gastric cancer patients using the Hallmark_angiogenesis gene set to score tumor transcriptomes. As we predicted, there was a significant correlation between angiogenesis score and expression of angiogenesis-related genes. The score moderately correlated with abundance of vessel-related stromal cells, fibroblasts and chondrocytes in the tumor microenvironment (TME). Tumors with high score had low infiltration of T helper type 1 and 2 cells but a greater infiltration of M1 macrophages and dendritic cells. They also had enriched expression of gene sets for coagulation, hypoxia, epithelial mesenchymal transition (EMT), and TGF-β signaling. High angiogenesis score was significantly associated with advanced AJCC stage and higher T- but not N-parameters in the TNM staging system. Patients with a high score also had shorter survival. In conclusion, bulk tumor transcriptome-based quantification of tumor angiogenesis using a computational algorithm may serve to identify patients with worse survival in gastric cancer.

Organoids Are Limited in Modeling the Colon Adenoma-Carcinoma Sequence

The colon adenoma-carcinoma sequence is a multistep genomic-altering process that occurs during colorectal cancer (CRC) carcinogenesis. Organoids are now commonly used to model both non-cancerous and cancerous tissue. This study aims to investigate how well organoids mimic tissues in the adenoma-carcinoma sequence by comparing their transcriptomes. A total of 234 tissue samples (48 adenomas and 186 CRC) and 60 organoid samples (15 adenomas and 45 CRC) were analyzed. We found that cell-proliferation-related gene sets were consistently enriched in both CRC tissues and organoids compared to adenoma tissues and organoids by gene set enrichment analysis (GSEA). None of the known pathways in the colon adenoma-carcinoma sequence were consistently enriched in CRC organoids. There was no enrichment of the tumor microenvironment-related gene sets in CRC organoids. CRC tissues enriched immune-response-related gene sets, whereas CRC organoids did not. The proportions of infiltrating immune cells were different between tissues and organoids, whereas there was no difference between cancer and adenoma organoids. The amounts of cancer stem cells and progenitor cells were not different between CRC and adenoma organoids, whereas a difference was noted between CRC and adenoma tissues. In conclusion, we demonstrated that organoids model only part of the adenoma-carcinoma sequence and should be used with caution after considering their limitations.

Th2 cell infiltrations predict neoadjuvant chemotherapy response of estrogen receptor-positive breast cancer

Background

High infiltration of Th2 is linked to breast cancer progression and metastasis through the induction of cytokine release and T-cell anergy. The estrogen receptor (ER)-positive subtype, which accounts for 70% of breast cancer, is known to respond less to neoadjuvant chemotherapy (NAC) due to its low potential for proliferation. We hypothesized that Th2 high tumors are highly proliferative, and thus more likely to respond to NAC in ER-positive breast cancer.

Methods

We obtained clinicopathological data and overall survival information on 1,069 breast cancer patients from The Cancer Genome Atlas (TCGA). Computational algorithms and CIBERSORT were used to estimate immune cell infiltration. Additionally, xCell was used for validation.

Results

Th2 high tumors did not consistently associate with an unfavorable immune cell composition and tumor immune microenvironment but were found to be significantly elevated in the cancer stage. Th2 high tumors also correlated with high Nottingham pathological grade, as well as with Ki-67 and proliferation score in ER-positive subtypes. High Th2 tumors achieved a pathological complete response (pCR) significantly higher in ER-positive breast cancer.

Conclusions

In conclusion, high levels of Th2 are associated with aggressive features of breast cancer. Th2 levels may be a biomarker in patient selection for NAC in ER-positive breast cancer.

High Expression of NRF2 Is Associated with Increased Tumor-Infiltrating Lymphocytes and Cancer Immunity in ER-Positive/HER2-Negative Breast Cancer

Simple Summary

The clinical relevance of Nuclear factor erythroid 2-Related Factor 2 (NRF2) in human breast cancer remains unclear. A total of 5443 breast cancer patients with transcriptomic profile were analyzed for the clinical relevance of NRF2 expression, including cancer aggressiveness, immune cell infiltration, patient survival, and drug response. We found that tumors with high NRF2 expression were associated with better survival in ER-positive/HER2-negative breast cancer. NRF2 expression was equivalent in immune, stromal, and cancer cells in tumor microenvironment. We found that high NRF2 expression was associated with enhanced tumor-infiltrating lymphocytes in ER-positive/HER2-negative breast cancer. NRF2 expression significantly correlated with drug sensitivity in multiple ER-positive breast cancer cell lines, but not associated with pathological complete response after neoadjuvant chemotherapy in breast cancer patients regardless of subtypes.

Abstract

Nuclear factor erythroid 2-related factor 2 (NRF2) is a key modifier in breast cancer. It is unclear whether NRF2 suppresses or promotes breast cancer progression. We studied the clinical relevance of NRF2 expression by conducting in silico analyses in 5443 breast cancer patients from several large patient cohorts (METABRIC, GSE96058, GSE25066, GSE20194, and GSE75688). NRF2 expression was significantly associated with better survival, low Nottingham pathological grade, and ER-positive/HER2-negative and triple negative breast cancer (TNBC). High NRF2 ER-positive/HER2-negative breast cancer enriched inflammation- and immune-related gene sets by GSEA. NRF2 expression was elevated in immune, stromal, and cancer cells. High NRF2 tumors were associated with high infiltration of immune cells (CD8⁺, CD4⁺, and dendritic cells (DC)) and stromal cells (adipocyte, fibroblasts, and keratinocytes), and with low fraction of Th1 cells. NRF2 expression significantly correlated with area under the curve (AUC) of several drug response in multiple ER-positive breast cancer cell lines, however, there was no significant association between NRF2 and pathologic complete response (pCR) rate after neoadjuvant chemotherapy in human samples. Finally, high NRF2 breast cancer was associated with high expression of immune checkpoint molecules. In conclusion, NRF2 expression was associated with enhanced tumor-infiltrating lymphocytes in ER-positive/HER2-negative breast cancer.

Inflammation Is Associated with Worse Outcome in the Whole Cohort but with Better Outcome in Triple-Negative Subtype of Breast Cancer Patients

Inflammation has been linked with cancer, but whether it is part of the problem or part of the solution remains to be a matter of debate in breast cancer. Our group and others have demonstrated that inflammation aggravates cancer progression; however, some claim that inflammation may support immune cell infiltration and suppress cancer. We defined the gene set variation analysis of the Molecular Signatures Database Hallmark inflammatory response gene set as the inflammatory pathway score and analyzed 3632 tumors in total from 4 breast cancer cohorts (METABRIC, TCGA, GSE25066, and GSE21094). In the whole breast cancer cohort, high-score tumors were associated with aggressive clinical characteristics, such as worse disease specific survival, higher Nottingham histological grade, and younger age. Inflammatory score was significantly higher in triple-negative (TNBC) as well as basal and normal subtypes compared with the other subtypes, which suggest that the detrimental effect of high level of inflammation may be because it includes a more aggressive subtype. On the contrary, high score within TNBC was significantly associated with better survival. TNBC with high score enriched not only IFN-α, IFN-γ response, IL-2/STAT5 signaling, Allograft rejection, Complement, p53 pathway, Reactive Oxygen, and Apoptosis but also TNF-α signaling, IL6-JAK-STAT signaling, TGF-β signaling, Coagulation, Angiogenesis, EMT, KRAS signaling, and PI3K-AKT-MTOR signaling gene sets. High score was associated with mainly favorable anticancerous immune cell infiltration as well as Leukocyte fraction, TIL regional fraction, Lymphocyte infiltration, IFN-γ response, TGF-β response, and cytolytic activity scores. Although the inflammatory pathway score was not associated with neoadjuvant treatment response, it associated with expressions of immune checkpoint molecules. In conclusion, inflammation was associated with worse outcome in the whole breast cancer cohort, but with better outcome in TNBC, which was associated with favorable anticancerous immune response and immune cell infiltrations.

Degree of Early Estrogen Response Predict Survival after Endocrine Therapy in Primary and Metastatic ER-Positive Breast Cancer

Simple Summary

Over 70% of breast cancer patients in the US have estrogen receptor (ER)-positive tumors. A better predictive biomarker of endocrine therapy would be useful to improve patient compliance. We found that estrogen response early score generated by a GSEA algorithm was significantly associated with immune cell infiltrations, patient survival, and endocrine therapy response in ER-positive breast cancer. Furthermore, the score may be a useful tool to predict response to endocrine therapy in both primary and metastatic breast cancer compared to ER gene expression. This study demonstrates that the estrogen response early score may be a useful prognostic and predicative biomarker in patients with either primary or metastatic breast cancer.

Abstract

Endocrine therapy is the gold-standard treatment for ER-positive/HER2-negative breast cancer. Although its clear benefit, patient compliance is poor (50–80%) due to its long administration period and adverse effects. Therefore, a predictive biomarker that can predict whether endocrine therapy is truly beneficial may improve patient compliance. In this study, we use estrogen response early gene sets of gene set enrichment assay algorithm as the score. We hypothesize that the score could predict the response to endocrine therapy and survival of breast cancer patients. A total of 6549 breast cancer from multiple patient cohorts were analyzed. The score was highest in ER-positive/HER2-negative compared to the other subtypes. Earlier AJCC stage, as well as lower Nottingham pathological grade, were associated with a high score. Low score tumors enriched only allograft rejection gene set, and was significantly infiltrated with immune cells, and high cytolytic activity score. A low score was significantly associated with a worse response to endocrine therapy and worse survival in both primary and metastatic breast cancer patients. The hazard ratio was double that of ESR1 expression. In conclusion, the estrogen response early score predicts response to endocrine therapy and is associated with survival in primary and metastatic breast cancer.

Abundance of Regulatory T Cell (Treg) as a Predictive Biomarker for Neoadjuvant Chemotherapy in Triple-Negative Breast Cancer

Simple Summary

Regulatory CD4⁺ T cell (Treg) is one of the suppressive immune cells, but data on its clinical relevance in large human breast cancer cohort is limited. Abundance of Tregs in 5177 breast cancer patient samples from five independent cohorts was analyzed by the xCell algorithm using tumor transcriptomics. Treg abundance was lower in metastatic tumors when compared to matched primary tumors. Treg was associated with a high mutation rate of TP53 genes and copy number mutations as well as with increased tumor infiltration of M2 macrophages and decreased infiltration of T helper type 1 cells. Interestingly, low Treg abundance was significantly associated with pathological complete response (pCR) after neoadjuvant chemotherapy (NAC) in TNBC, but not in ER-positive/Her2-negative subtype. Abundance of Treg was also associated with high expression of multiple immune checkpoint molecules. In conclusion, Treg abundance may have a potential as a predictive biomarker of pCR after NAC in TNBC.

Abstract

Regulatory CD4⁺ T cell (Treg), a subset of tumor-infiltrating lymphocytes (TILs), are known to suppress anticancer immunity but its clinical relevance in human breast cancer remains unclear. In this study, we estimated the relative abundance of Tregs in breast cancer of multiple patient cohorts by using the xCell algorithm on bulk tumor gene expression data. In total, 5177 breast cancer patients from five independent cohorts (TCGA-BRCA, GSE96058, GSE25066, GSE20194, and GSE110590) were analyzed. Treg abundance was not associated with cancer aggressiveness, patient survival, or immune activity markers, but it was lower in metastatic tumors when compared to matched primary tumors. Treg was associated with a high mutation rate of TP53 genes and copy number mutations as well as with increased tumor infiltration of M2 macrophages and decreased infiltration of T helper type 1 (Th1) cells. Pathological complete response (pCR) after neoadjuvant chemotherapy (NAC) was significantly associated with low Treg abundance in triple negative breast cancer (TNBC) but not in ER-positive/Her2-negative subtype. High Treg abundance was significantly associated with high tumor expression of multiple immune checkpoint inhibitor genes. In conclusion, Treg abundance may have potential as a predictive biomarker of pCR after NAC in TNBC.

M1 Macrophage and M1/M2 ratio defined by transcriptomic signatures resemble only part of their conventional clinical characteristics in breast cancer

Tumor associated macrophages (TAMs) play a critical role in biology of various cancers, including breast cancer. In the current study, we defined “M1” macrophage and “M1”/“M2” ratio by transcriptomic signatures using xCell. We investigated the association between high level of “M1” macrophage or “M1”/“M2” ratio and the tumor immune microenvironment by analyzing the transcriptome of publicly available cohorts, TCGA and METABRIC. We found that “M1” high tumors were not associated with prolonged survival compared with “M1” low tumors, or with the response to neoadjuvant chemotherapy. “M1” high tumors were associated with clinically aggressive features and “M1” high tumors enriched the cell proliferation and cell cycle related gene sets in GSEA. At the same time, “M1” high tumors were associated with high immune activity and favorable tumor immune microenvironment, as well as high expression of immune check point molecules. Strikingly, all these results were mirrored in “M1”/“M2” ratio high tumors. In conclusion, transcriptomically defined “M1” or “M1”/“M2” high tumors were associated with aggressive cancer biology and favorable tumor immune microenvironment but not with survival benefit, which resembled only part of their conventional clinical characteristics.

High G2M Pathway Score Pancreatic Cancer is Associated with Worse Survival, Particularly after Margin-Positive (R1 or R2) Resection

Simple Summary

The G2M checkpoint pathway is a critical step in the cell cycle, which is one of the hallmarks in cancer. We investigated clinical relevance of the G2M pathway in pancreatic cancer, using gene set variation analysis (GSVA) with Hallmark G2M checkpoint gene set. High G2M score tumors enriched several cell proliferation gene sets as well as MKI67 expression, pathological grade, and proliferation score. Furthermore, the score was predictive of disease-specific survival in pancreatic cancer. High G2M tumor was associated with high mutation rate of KRAS and TP53, and significantly enriched these pathway gene sets, as well as high infiltration of Th2 cells. High G2M score consistently associated with worse overall survival in multiple cohorts, particularly in R1/2 resection, but not in R0.

Abstract

Pancreatic cancer is highly mortal due to uncontrolled cell proliferation. The G2M checkpoint pathway is an essential part of the cell cycle. We hypothesized that a high G2M pathway score is associated with cell proliferation and worse survival in pancreatic cancer patients. Gene set variation analysis using the Hallmark G2M checkpoint gene set was used as a score to analyze a total of 390 human pancreatic cancer patients from 3 cohorts (TCGA, GSE62452, GSE57495). High G2M score tumors enriched other cell proliferation genes sets as well as MKI67 expression, pathological grade, and proliferation score. Independent of other prognostic factors, G2M score was predictive of disease-specific survival in pancreatic cancer. High G2M tumor was associated with high mutation rate of KRAS and TP53 and significantly enriched these pathway gene sets, as well as high infiltration of Th2 cells. High G2M score consistently associated with worse overall survival in 3 cohorts, particularly in R1/2 resection, but not in R0. High G2M tumor in R1/2 highly enriched metabolic and cellular components’ gene sets compared to R0. To our knowledge, this is the first study to use gene set variation analysis as a score to examine the clinical relevancy of the G2M pathway in pancreatic cancer.

ITPKC as a Prognostic and Predictive Biomarker of Neoadjuvant Chemotherapy for Triple Negative Breast Cancer

Triple negative breast cancer (TNBC) is the most aggressive subtype of breast cancer with higher mortality than the others. Pathological complete response (pCR) to neoadjuvant chemotherapy (NAC) is considered as a surrogate to predict survival. Inositol 1,4,5-trisphosphate 3-kinase C (ITPKC) is a negative regulator of T cell activation, and reduction in ITPKC function is known to promote Kawasaki disease. Given the role of tumor infiltrating lymphocytes in NAC and since TNBC has the most abundant immune cell infiltration in breast cancer, we hypothesized that the ITPKC expression level is associated with NAC response and prognosis in TNBC. The ITPKC gene was expressed in the mammary gland, but its expression was highest in breast cancer cells among other stromal cells in a bulk tumor. ITPKC expression was highest in TNBC, associated with its survival, and was its independent prognostic factor. Although high ITPKC was not associated with immune function nor with any immune cell fraction, low ITPKC significantly enriched cell proliferation-related gene sets in TNBC. TNBC with low ITPKC achieved a significantly higher pCR rate after NAC. To the best of our knowledge, this is the first report to demonstrate that ITPKC gene expression may be useful as a prognostic and predictive biomarker in TNBC.

CD8 T Cell Score as a Prognostic Biomarker for Triple Negative Breast Cancer

CD8 T cell is an essential component of tumor-infiltrating lymphocytes (TIL) and tumor immune microenvironment (TIME). Using the xCell CD8 T cell score of whole tumor gene expression data, we estimated these cells in total of 3837 breast cancer patients from TCGA, METABRIC and various GEO cohorts. The CD8 score correlated strongly with expression of CD8 genes. The score was highest for triple-negative breast cancer (TNBC), and a high score was associated with high tumor immune cytolytic activity and better survival in TNBC but not other breast cancer subtypes. In TNBC, tumors with a high CD8 score had enriched expression of interferon (IFN)-α and IFN-γ response and allograft rejection gene sets, and greater infiltration of anti-cancerous immune cells. The score strongly correlated with CD4 memory T cells in TNBC, and tumors with both a high CD8 score and high CD4 memory T cell abundance had significantly better survival. Finally, a high CD8 score was significantly associated with high expression of multiple immune checkpoint molecules. In conclusion, a high CD8 T cell score is associated with better survival in TNBC, particularly when tumor CD4 memory T cells were elevated. Our findings also suggest a possible use of the score as a predictive biomarker for response to immune checkpoint therapy.

Intra-Tumoral Angiogenesis Is Associated with Inflammation, Immune Reaction and Metastatic Recurrence in Breast Cancer

Angiogenesis is one of the hallmarks of cancer. We hypothesized that intra-tumoral angiogenesis correlates with inflammation and metastasis in breast cancer patients. To test this hypothesis, we generated an angiogenesis pathway score using gene set variation analysis and analyzed the tumor transcriptome of 3999 breast cancer patients from The Cancer Genome Atlas Breast Cancer (TCGA-BRCA), Molecular Taxonomy of Breast Cancer International Consortium (METABRIC), GSE20194, GSE25066, GSE32646, and GSE2034 cohorts. We found that the score correlated with expression of various angiogenesis-, vascular stability-, and sphingosine-1-phosphate (S1P)-related genes. Surprisingly, the angiogenesis score was not associated with breast cancer subtype, Nottingham pathological grade, clinical stage, response to neoadjuvant chemotherapy, or patient survival. However, a high score was associated with a low fraction of both favorable and unfavorable immune cell infiltrations except for dendritic cell and M2 macrophage, and with Leukocyte Fraction, Tumor Infiltrating Lymphocyte Regional Fraction and Lymphocyte Infiltration Signature scores. High-score tumors had significant enrichment for unfavorable inflammation-related gene sets (interleukin (IL)6, and tumor necrosis factor (TNF)α- and TGFβ-signaling), as well as metastasis-related gene sets (epithelial mesenchymal transition, and Hedgehog-, Notch-, and WNT-signaling). High score was significantly associated with metastatic recurrence particularly to brain and bone. In conclusion, using the angiogenesis pathway score, we found that intra-tumoral angiogenesis is associated with immune reaction, inflammation and metastasis-related pathways, and metastatic recurrence in breast cancer.

Intratumoral Adipocyte-High Breast Cancer Enrich for Metastatic and Inflammation-Related Pathways but Associated with Less Cancer Cell Proliferation

Cancer-associated adipocytes are known to cause inflammation, leading to cancer progression and metastasis. The clinicopathological and transcriptomic data from 2256 patients with breast cancer were obtained based on three cohorts: The Cancer Genome Atlas (TCGA), GSE25066, and a study by Yau et al. For the current study, we defined the adipocyte, which is calculated by utilizing a computational algorithm, xCell, as “intratumoral adipocyte”. These intratumoral adipocytes appropriately reflected mature adipocytes in a bulk tumor. The amount of intratumoral adipocytes demonstrated no relationship with survival. Intratumoral adipocyte-high tumors significantly enriched for metastasis and inflammation-related gene sets and are associated with a favorable tumor immune microenvironment, especially in the ER+/HER2- subtype. On the other hand, intratumoral adipocyte-low tumors significantly enriched for cell cycle and cell proliferation-related gene sets. Correspondingly, intratumoral adipocyte-low tumors are associated with advanced pathological grades and inversely correlated with MKI67 expression. In conclusion, a high amount of intratumoral adipocytes in breast cancer was associated with inflammation, metastatic pathways, cancer stemness, and favorable tumor immune microenvironment. However, a low amount of adipocytes was associated with a highly proliferative tumor in ER-positive breast cancer. This cancer biology may explain the reason why patient survival did not differ by the amount of adipocytes.

The E2F Pathway Score as a Predictive Biomarker of Response to Neoadjuvant Therapy in ER+/HER2- Breast Cancer

E2F transcription factors play critical roles in the cell cycle. Therefore, their activity is expected to reflect tumor aggressiveness and responsiveness to therapy. We scored 3905 tumors of nine breast cancer cohorts for this activity based on their gene expression for the Hallmark E2F targets gene set. As expected, tumors with a high score had an increased expression of cell proliferation-related genes. A high score was significantly associated with shorter patient survival, greater MKI67 expression, histological grade, stage, and genomic aberrations. Furthermore, metastatic tumors had higher E2F scores than the primary tumors from which they arose. Although tumors with a high score had greater infiltration by both pro- and anti-cancerous immune cells, they had an increased expression of immune checkpoint genes. Estrogen receptor (ER)-positive/human epidermal growth factor receptor 2 (HER2)-negative cancer with a high E2F score achieved a significantly higher pathological complete response (pCR) rate to neoadjuvant chemotherapy. The E2F score was significantly associated with the expression of cyclin-dependent kinase (CDK)-related genes and strongly correlated with sensitivity to CDK inhibition in cell lines. In conclusion, the E2F score is a marker of breast cancer aggressiveness and predicts the responsiveness of ER-positive/HER2-negative patients to neoadjuvant chemotherapy and possibly to CDK and immune checkpoint inhibitors.

Contribution of Immune Cells to Glucocorticoid Receptor Expression in Breast Cancer

Breast cancer (BC) patients experience increased stress with elevated cortisol levels, increasing risk of cancer recurrence. Cortisol binds to a cytoplasmic receptor, glucocorticoid receptor (GR) encoded by GR gene (NR3C1). We hypothesized that not only cancer cells, but even immune cells in the tumor microenvironment (TME) may contribute to GR expression in bulk tumor and influence prognosis. To test this, mRNA expression data was accessed from METABRIC and TCGA. "High" and "low" expression was based on highest and lowest quartiles of NR3C1 gene expression, respectively. Single-cell sequencing data were obtained from GSE75688 and GSE114725 cohorts. Computer algorithms CIBERSORT, Gene Set Enrichment Analysis and TIMER were used. GR-high BC has better median disease-free and disease-specific survival. Single cell sequencing data showed higher GR expression on immune cells compared to cancer and stromal cells. Positive correlation between GR-high BC and CD8⁺ T-cells was noted. In GR-high tumors, higher cytolytic activity (CYT) with decreased T-regulatory and T-follicular helper cells was observed. High GR expression was associated with lower proliferation index Ki67, enriched in IL-2_STAT5, apoptosis, KRAS, TGF-β signaling, and epithelial-to-mesenchymal transition. Immune cells significantly contribute to GR expression of bulk BC. GR-high BC has a favorable TME with higher CYT with favorable outcomes.

Clinical relevance of tumor microenvironment: immune cells, vessels, and mouse models

The tumor microenvironment (TME) plays a crucial role in tumor progression, therapeutic response, and patient outcomes. TME includes immune cells, blood and lymphatic vessels, and so on. There are anti-cancer and pro-cancer immune cells. In general, infiltration of anti-cancer immune cells, such as cytotoxic T cells (CTLs), is associated with a favorable patient prognosis. In contrast, infiltration of pro-cancer immune cells, such as regulatory T cells (Tregs), tumor-associated macrophages (TAMs) and myeloid-derived suppressor cells (MDSCs), is associated with a worse prognosis. However, some immune cells, which play an ambivalent role in cancer immunity, have demonstrated contradictory impacts on patient prognosis. Blood and lymphatic vessels play crucial roles in TME not only as delivery and draining systems of fluid and molecules, but also allowing cancer cells access to systematic circulation to metastasize. Angiogenesis promotes cancer aggressiveness and is associated with a worse prognosis. Its targeted therapy shows a benefit in some cancers, however, because the target can vary by caner type, a benefit of anti-angiogenesis therapy is limited in the current standard of care. Lymphangiogenesis plays a role in lymph node metastasis, thus, it is associated with a poor prognosis in some cancers. To study TME, the mouse model is one of the most commonly used tools. The choice of appropriate mouse model depends on the hypothesis being tested and the scientific question being asked. Here, we review recent studies that investigated the clinical relevance of TME components and introduce mouse models to study TME.