Search

Simple Summary: Early-stage invasive lobular breast cancer (ILC) is characterized by multifocal tumor growth in the breast and a distinct pattern of late metastatic spread to other tissues. ILC cells are hypothesized to initiate metastases by exiting the breast via blood and lymphatic channels early in the disease process and then invading and eventually growing in distant tissues. Using in vitro ILC models, this study reveals that expression and activation of glucocorticoid receptor (GR), a stress-hormone-activated nuclear receptor and transcription factor, resulted in inhibition of ILC cell proliferation. Unexpectedly, GR activation also appeared to increase gene expression pathways that promote metastases. Thus, GR may be an important modulator of the low proliferative rate and high late metastatic risk associated with ILC. Estrogen receptor-positive (ER+) invasive lobular breast cancer (ILC) comprises about ~15% of breast cancer. ILC's unique genotypic (loss of wild type E-cadherin expression) and phenotypic (small individual round cancer cells that grow in discontinuous nests) are thought to contribute to a distinctive pattern of metastases to serosal membranes. Unlike invasive ductal carcinoma (IDC), ILC metastases often intercalate into the mesothelial layer of the peritoneum and other serosal surfaces. While ER activity is a known driver of ILC proliferation, very little is known about how additional nuclear receptors contribute to ILC's distinctive biology. In ER+ IDC, we showed previously that glucocorticoid receptor (GR) activity inhibits pro-proliferative gene expression and cell proliferation. Here we examined ER+ ILC models and found that GR activation similarly reduces S-phase entry gene expression and ILC proliferation. While slowing tumor growth rate, our data also suggest that GR activation results in an enhanced metastatic phenotype through increasing integrin-encoding gene expression, extracellular matrix protein adhesion, and mesothelial cell clearance. Moreover, in an intraductal mouse mammary gland model of ILC, we found that GR expression is associated with increased bone metastases despite slowed primary mammary tumor growth. Taken together, our findings suggest GR-mediated gene expression may contribute to the unusual characteristics of ILC biology. [ABSTRACT FROM AUTHOR]

Simple Summary: Inactivating mutations in the CDH1 gene, encoding the cell adhesion protein E-cadherin, cause hereditary diffuse gastric cancer syndrome (HDGC), as well as being a hallmark of sporadic diffuse gastric cancers and lobular breast cancers. We have previously identified AKT3 as a potential vulnerability in gastric cancers lacking CDH1 expression. This study aimed to test whether drugs which inhibit the AKT3-associated gene, discoidin domain receptor tyrosine kinase 2 (DDR2) specifically targeted cells deficient in E-cadherin. We demonstrated that cells and organoids lacking E-cadherin exhibited heightened sensitivity to dasatinib, a drug that targets multiple kinases including DDR2 and SRC. The CDH1 gene, encoding the cell adhesion protein E-cadherin, is one of the most frequently mutated genes in gastric cancer and inactivating germline CDH1 mutations are responsible for the cancer syndrome hereditary diffuse gastric cancer (HDGC). CDH1-deficient gastric cancers exhibit high AKT serine/threonine kinase 3 (AKT3) expression, but specific drugs against this AKT isoform are not available. We therefore used two publicly available datasets to identify AKT3-associated genes which could be used to indirectly target AKT3. Reactome analysis identified an enrichment of extracellular matrix remodelling genes in AKT3-high gastric cancers. Of the 51 genes that were significantly correlated with AKT3 (but not AKT1), discoidin domain receptor tyrosine kinase 2 (DDR2) showed the strongest positive association. Treatment of isogenic human cells and mouse gastric and mammary organoids with dasatinib, a small molecule inhibitor of multiple kinases including SRC, BCR-ABL and DDR2, preferentially slowed the growth and induced apoptosis of E-cadherin-deficient cells. Dasatinib treatment also preferentially slowed the growth of gastric and mammary organoids harbouring both Cdh1 and Tp53 mutations. In organoid models, dasatinib treatment was associated with decreased phosphorylation of total AKT, with a stronger effect seen in Cdh1-deficient organoids. Treatment with combinations of dasatinib and an inhibitor of AKT, MK2206, enhanced the effect of dasatinib in breast MCF10A cells. In conclusion, targeting the DDR2-SRC-AKT3 axis with dasatinib represents a promising approach for the chemoprevention and chemotherapy of gastric and breast cancers lacking E-cadherin. [ABSTRACT FROM AUTHOR]

Background: Vitamin D (vitD) may be involved in different extraskeletal conditions as well as skeletal muscle diseases. It has been hypothesized that, at least in part, a low level of vitD could contribute to facilitating cancer development. Breast cancer (BC) seems to be associated with low levels of vitD. Materials and methods: This was an observational retrospective evaluation of 87 women (mean age: 54 ± 12 years old) who underwent surgery for the treatment of BC. Our main purpose was to correlate the types of BC and the levels of vitD. Results: A positive significant correlation (R > 0.7) was found between non-invasive carcinoma in situ and 25(OH)D levels and age (R = 0.82, p < 0.05). A positive, but nonsignificant, correlation was reported between invasive ductal carcinoma and 25(OH)D and age (R = 0.45, p > 0.05). A negative but nonsignificant correlation was found between invasive lobular carcinoma and 25(OH)D and age (R = 0.24, p > 0.05). Discussion and Conclusions: We did not find a significant relationship between vitD and BC subtypes. Considering the positive significant correlation between vitD levels and age for in situ BC, although preliminary, our results seem to suggest a possible role of vitD in in situ BC. However, these findings need to be confirmed in larger studies. [ABSTRACT FROM AUTHOR]

Simple Summary: High intratumoral stromal content is related to worse outcomes in several types of cancer. However, its prognostic role in breast cancer seems to differ between different subtypes. High intratumoral stromal content is a negative prognostic marker in triple-negative breast cancer, while the opposite is the case for estrogen-receptor-positive breast cancer, in which higher stromal content is indicative of a better prognosis. Most lobular breast cancers are estrogen-receptor-positive, and the tumor tissue has a clearly defined histological appearance, often with a high intratumoral stromal content. To date, the prognostic role of intratumoral stromal content in lobular breast cancer remains unclear. In this study, we aimed to investigate the prognostic importance of intratumoral stromal content in estrogen-receptor-positive lobular breast cancer. Our results show that high intratumoral stromal content is an easily assessed and clinically useful indicator of a good prognosis in lobular breast cancer. Previous studies have shown that high intratumoral stromal content is associated with a worse prognosis in breast cancer, especially in the triple-negative subtype. However, contradictory results have been reported for estrogen-receptor-positive (ER+) breast cancer, indicating that the prognostic role of intratumoral stromal content may be subtype-dependent. In this study, we investigated the importance of intratumoral stromal content for breast cancer-specific mortality (BCM) in a well-defined subgroup (n = 182) of ER+/human-epidermal growth-factor-receptor-2 negative (HER2−) invasive lobular breast cancer (ILC). The intratumoral stromal content was assessed on hematoxylin–eosin-stained whole sections and graded into high stroma (>50%) or low stroma (≤50%). A total of 82 (45%) patients had high-stroma tumors, and 100 (55%) had low-stroma tumors. High-stroma tumors were associated with a lower Nottingham histological grade, low Ki67, and a luminal A-like subtype. After a 10-year follow-up, the patients with high-stroma tumors had a lower BCM (HR: 0.43, 95% CI: 0.21–0.89, p = 0.023) in univariable analysis. Essentially the same effect was found in both the multivariable analysis (10-year follow-up) and univariable analysis (25-year follow-up), but these findings were not strictly significant. In ER+/HER2− ILC, high intratumoral stromal content is an easily assessable histological indicator of a good prognosis. [ABSTRACT FROM AUTHOR]

Simple Summary: Invasive lobular breast cancer (ILC) accounts for approximately 5–15% of breast cancers, and although response rates to treatments are initially good, an ILC diagnosis is associated with adverse long-term outcomes; better treatments, specifically targeted to this sub-type of breast cancer, are required to improve patient survival. The tumor microenvironment (TME) plays an important role in determining how cancers respond to treatment, and in this study, we carried out an in-depth analysis of the TME in ILC following laser-capture microdissection of the tumor stroma, and analysis of primary cancer-associated fibroblasts (CAFs), which comprise the majority of non-malignant cells within tumors. This identified changes in genes involved in regulation of the extracellular matrix and also growth factor signaling pathways that were differentially regulated in ILC. Further analysis of breast cancer datasets showed that two of these genes which encode a secreted metalloproteinase (PAPPA) and a metalloproteinase inhibitor (TIMP2) were associated with survival outcomes in ILC. Invasive lobular carcinoma (ILC) is the second most common histological subtype of breast cancer, and it exhibits a number of clinico-pathological characteristics distinct from the more common invasive ductal carcinoma (IDC). We set out to identify alterations in the tumor microenvironment (TME) of ILC. We used laser-capture microdissection to separate tumor epithelium from stroma in 23 ER+ ILC primary tumors. Gene expression analysis identified 45 genes involved in regulation of the extracellular matrix (ECM) that were enriched in the non-immune stroma of ILC, but not in non-immune stroma from ER+ IDC or normal breast. Of these, 10 were expressed in cancer-associated fibroblasts (CAFs) and were increased in ILC compared to IDC in bulk gene expression datasets, with PAPPA and TIMP2 being associated with better survival in ILC but not IDC. PAPPA, a gene involved in IGF-1 signaling, was the most enriched in the stroma compared to the tumor epithelial compartment in ILC. Analysis of PAPPA- and IGF1-associated genes identified a paracrine signaling pathway, and active PAPP-A was shown to be secreted from primary CAFs. This is the first study to demonstrate molecular differences in the TME between ILC and IDC identifying differences in matrix organization and growth factor signaling pathways. [ABSTRACT FROM AUTHOR]

Simple Summary: Some patients carry a mutated copy of the CDH1 gene that can lead to a very rare form of hereditary gastric cancer called signet-ring cell adenocarcinoma (SRCC). SRCCs rarely form visible tumors prior to spreading. Hence, patients are recommended to have prophylactic gastrectomies at a young age. Many patients wish to avoid surgery and thus have regular checks with upper endoscopy with biopsies to rule out cancer. Further, these patients may also be at risk of other cancers beyond the already known breast cancer risks, but this is not known. In this study, we show that despite systematic biopsy protocols, many early cancers might be missed on endoscopy. Therefore, patients should not rely on endoscopy to delay surgery. These patients may also be at increased risk of colorectal SRCC, which has very poor survival outcomes. To confirm this, we need a central database that captures outcomes for this patient population. Hereditary diffuse gastric cancer (HDGC) is a rare signet-ring cell adenocarcinoma (SRCC) linked to CDH1 (E-cadherin) inactivating germline mutations, and increasingly other gene mutations. Female CDH1 mutation carriers have additional risk of lobular breast cancer. Risk management includes prophylactic total gastrectomy (PTG). The utility of endoscopic surveillance is unclear, as early disease lacks macroscopic lesions. The current systematic biopsy protocols have unknown efficacy, and other secondary cancer risks are postulated. We conducted a retrospective study of consecutive asymptomatic HDGC patients undergoing PTG, detailing endoscopic, pathologic, and outcome results. A systematic review compared endoscopic biopsy foci detection via random sampling versus Cambridge Protocol against PTG findings. A population-level secondary-cancer-risk postulation among sporadic gastric SRCC patients was completed using the Surveillance, Epidemiology, and End Results database. Of 97 patients, 67 underwent PTG, with 25% having foci detection on random endoscopic biopsy despite 75% having foci on final pathology. There was no improvement in the endoscopic detection rate by Cambridge Protocol. The postulated hazard ratio among sporadic gastric SRCC patients for a secondary colorectal SRCC was three-fold higher, relative to conventional adenocarcinoma patients. Overall, HDGC patients should not rely on endoscopic surveillance to delay PTG, and may have secondary SRCC risks. A definitive determination of actual risk requires collaborative patient outcome data banking. [ABSTRACT FROM AUTHOR]

Simple Summary: Diffuse gastric cancer is the hallmark of the hereditary diffuse gastric cancer syndrome related with the E-cadherin germline mutations. Other cancers (non-gastric) are described in association with the CDH1 gene germline alterations. In this study, we aimed to assess the overall frequency of CDH1 mutations in non-gastric tumors reported in literature so far. Hereditary Diffuse Gastric Cancer (HDGC) is a complex inherited syndrome caused by CDH1 germline mutations. DGC is the hallmark cancer of this genetic predisposition, but several other cancers are associated with these CDH1 mutations. In this review, we revised all studies reporting CDH1 mutations in non-GC patients. The selected studies included: (a) families aggregating with GC and other cancers, both, and (b) families presenting only non-gastric tumors association. Among non-gastric tumors, our results show that CDH1 mutations are most frequently identified in breast cancer. The frequency of missense mutations is higher in the non-GC group, as the age at diagnosis in this group. Moreover, the predominant CDH1 mutation affects the extracellular domain. Our data suggest that CDH1 genetic testing should be considered also in other cancers, especially breast tumors. [ABSTRACT FROM AUTHOR]

The currently used immunohistochemical approach in determining the estrogen receptor (ER) positivity of breast cancers (BCs) is inherently subjective and additionally limited by its semi-quantitative nature. The application of software in the analysis of digitized slide images may overcome some of these limitations. However, the utilization of such an approach requires that the entire staining procedure is standardized., Background and Objectives: We aimed to establish a procedure for the photometric and morphometric analysis of BC immunohistochemical parameters that can possibly be used for a diagnostic purpose that is in line with the current semi-quantitative scoring system., Materials and Methods: Semi-quantitative analysis of ER-stained tissue sections was performed following the Allred scoring system guidelines. The quantitative analysis was performed in ImageJ software after color deconvolution. The quantitative analysis of 66 cases of invasive lobular BC included: Percent of ER-positive cells, average nuclear coloration intensity, and the quantitative ER score. The percent of ER-positive tumor cells was counted using a standard grid overlay, while optical density (0.0-1.0) was measured within each nucleus at the grid points., Results: A statistical analysis revealed a significant positive correlation ( r = 0.886, p < 0.001) between the subjective semi-quantitative and quantitative ER scores, with a large effect size ( d = 3.8215). We observed strong statistically significant correlations between individual parameters of the total ER score, percentage of ER-positive nuclei, and color intensity, obtained by the two independent methods., Conclusions: Additionally, besides excluding subjectivity, the up to now unreported cases of 3 + 0, 4 + 0, and 5 + 0 Allred scores were detected only by the application of the proposed quantitative approach.