The examination of hematoxylin and eosin (H&E)-stained tissues on glass slides by conventional light microscopy is the foundation for histopathological diagnosis. However, this conventional method has some limitations in x-y axes due to its relatively narrow range of observation area and in z-axis due to its two-dimensionality. In this study, we applied a CUBIC pipeline, which is the most powerful tissue-clearing and three-dimensional (3D)-imaging technique, to clinical pathology. CUBIC was applicable to 3D imaging of both normal and abnormal patient-derived, human lung and lymph node tissues. Notably, the combination of deparaffinization and CUBIC enabled 3D imaging of specimens derived from paraffin-embedded tissue blocks, allowing quantitative evaluation of nuclear and structural atypia of an archival malignant lymphoma tissue. Furthermore, to examine whether CUBIC can be applied to practical use in pathological diagnosis, we performed a histopathological screening of a lymph node metastasis based on CUBIC, which successfully improved the sensitivity in detecting minor metastatic carcinoma nodules in lymph nodes. Collectively, our results indicate that CUBIC significantly contributes to retrospective and prospective clinicopathological diagnosis, which might lead to the establishment of a novel field of medical science based on 3D histopathology.

Lung cancer is a common type of cancer that represents a health problem worldwide; lung adenocarcinoma (LUAD) is a major subtype of lung cancer. Although several treatments for LUAD have been developed, the mortality rate remains high because of uncontrollable progression. Further biological and clinicopathological studies are therefore needed. Here, we investigated the role of family with sequence similarity 111 member B (FAM111B), which is highly expressed in papillary‐predominant LUAD; however, its role in cancer is unclear. An immunohistochemical analysis confirmed that papillary‐predominant adenocarcinomas exhibited higher expression of FAM111B, compared with lepidic‐predominant adenocarcinomas. Additionally, FAM111B expression was significantly correlated with clinical progression. In vitro functional analyses using FAM111B‐knockout cells demonstrated that FAM111B plays an important role in proliferation and cell cycle progression of KRAS ‐driven LUAD under serum‐starvation conditions. Furthermore, FAM111B regulated cyclin D1‐CDK4‐dependent cell cycle progression by degradation of p16. In summary, we revealed the clinical importance of FAM111B in human tumor tissues, as well as its function as a degradative enzyme. Therefore, FAM111B has potential as a clinicopathological prognostic marker for LUAD.

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Cancer-associated fibroblasts (CAFs) and tumor-associated macrophages (TAMs) in tumor stroma play a key role in disease progression. Recent studies using mice models suggest that CAFs are partly derived from bone marrow and TAMs primarily originate from bone marrow-derived inflammatory monocytes. However, the origin of these cells in humans remains unclear. Hence, we investigated their human origin, using specimens from human secondary tumors that developed after sex-mismatched bone marrow transplantation, by modified immunofluorescent in situ hybridization analysis and triple immunostaining. We observed that most of the α-smooth muscle actin (αSMA)-positive CAFs in the mammary gland, liver, and oral mucosa specimens obtained 3–19 years after bone marrow transplantation are recipient-derived cells. In contrast, the majority of the peritumoral αSMA-negative fibroblast-like cells are actually bone marrow-derived HLA-DR-positive myeloid cells, such as macrophages and dendritic cells. Furthermore, almost all CD163-positive TAMs and macrophages present in the non-tumor areas are derived from bone marrow.

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Adenylosuccinate lyase (ADSL) is an enzyme that plays important roles in de novo purine synthesis. Although ADSL was reported to be upregulated in various malignancies, such as colorectal, breast, and prostate cancer, as well as gliomas, the mechanism by which elevated ADSL expression contributes to cancer has not been elucidated. We previously performed a shotgun proteomics analysis to characterize specific proteins associated with the properties of the aldehyde dehydrogenase (ALDH)-high cell population, which was reported to be involved in tumorigenic potential, and showed that ADSL expression is upregulated in the ALDH-high population of endometrial cancer. Here, we showed that ADSL is involved in endometrial cancer aggressiveness by regulating expression of killer cell lectin-like receptor C3 (KLRC3), which is a receptor expressed on natural killer cells. Immunohistochemical analysis indicated that ADSL expression increased as endometrioid carcinoma specimens became more poorly differentiated and higher degree of primary tumor progression. Knockdown of ADSL in endometrial cancer cells decreased cell proliferation, migration, and invasive capability, and caused the cells to adopt a more rounded shape. DNA microarray analysis and quantitative real-time PCR showed that KLRC3 expression was decreased in ADSL knockdown cells. Knockdown of KLRC3 in endometrial cancer cells resulted in the same phenotype as knockdown of ADSL. Moreover, fumarate, which could be produced by ADSL and was recently shown to be an oncometabolite, recovered KLRC3 expression in ADSL knockdown cells, suggesting that fumarate produced by ADSL could regulate KLRC3 expression. Our findings indicate that ADSL enhances cell proliferation, migration, and invasive capability through regulation of KLRC3 expression by fumarate.

Endometrioid carcinoma (EC) is one of the most common malignancies of the female genital system. Although the behavior of EC ranges from an excellent prognosis to aggressive disease with a poor outcome, the factors that determine its diversity have not been determined. Here, we show that S100A4, a calcium‐binding protein of the EF‐hand type, is correlated with the proliferation and invasion ability of EC. We demonstrated previously that EC cells with high aldehyde dehydrogenase (ALDH) activity were more tumorigenic than ALDH‐lo cells. Screening by shotgun proteomics demonstrated that the expression level of S100A4 in ALDH‐hi EC cells was significantly higher than that in ALDH‐lo cells. S100A4‐knockout cells generated by the CRISPR/Cas9 system showed reduced proliferation and invasion. These cells showed impaired AKT phosphorylation and matrix metalloproteinase‐2 activation, accounting for their impaired proliferation and invasion, respectively. Furthermore, in clinical EC samples, elevated expression of S100A4 was highly related to myometrial and lymphatic invasion in well to moderately differentiated EC. Notably, strong and diffuse expression of S100A4 was observed in tumor tissues with a microcystic, elongated and fragmented (“MELF”) pattern, which is associated with a highly invasive EC phenotype. Collectively, our results demonstrate not only that high expression of S100A4 contributes to an aggressive phenotype of EC, but also that its elevated expression is closely related to the MELF histopathological pattern.

A population of mesenchymal stem cells, termed CXC chemokine ligand (CXCL)12-abundant reticular (CAR) cells or leptin receptor-expressing cells, are the major cellular component of niches for haematopoietic stem cells (HSCs) in murine bone marrow. CAR cells are characterized by several salient features, including much higher expression of CXCL12, stem cell factor (SCF), forkhead box C1 (FOXC1) and early B-cell factor 3 (EBF3), which are essential for HSC maintenance, than other cells. However, the human counterpart of CAR cells has not been fully described. Here, we show the presence of cells expressing much higher CXCL12 than other cells in human adult bone marrow using a flow cytometry-based in situ technique that enables high-throughput detection of mRNA at single-cell resolution. Most CXCL12 hi cells expressed high levels of SCF, FOXC1 and EBF3 and had the potential to differentiate into adipocytes and osteoblasts. Histologically, the nuclei of CXCL12 hi cells were identified and quantified by EBF3 expression in fixed marrow sections. CXCL12 hi cells sorted from residual bone marrow aspirates of chronic myeloid leukaemia patients expressed reduced levels of CXCL12, SCF, FOXC1 and EBF3 in correlation with increased leukaemic burden. Together, we identified the human counterpart of CAR cells, enabling the evaluation of their alterations in various haematological disorders by flow cytometric and histological analyses.