Evolutionary histories of breast cancer and related clones.

Recent studies have documented frequent evolution of clones carrying common cancer mutations in apparently normal tissues, which are implicated in cancer development1-3. However, our knowledge is still missing with regard to what additional driver events take place in what order, before one or more of these clones in normal tissues ultimately evolve to cancer. Here, using phylogenetic analyses of multiple microdissected samples from both cancer and non-cancer lesions, we show unique evolutionary histories of breast cancers harbouring der(1;16), a common driver alteration found in roughly 20% of breast cancers. The approximate timing of early evolutionary events was estimated from the mutation rate measured in normal epithelial cells. In der(1;16)(+) cancers, the derivative chromosome was acquired from early puberty to late adolescence, followed by the emergence of a common ancestor by the patient's early 30s, from which both cancer and non-cancer clones evolved. Replacing the pre-existing mammary epithelium in the following years, these clones occupied a large area within the premenopausal breast tissues by the time of cancer diagnosis. Evolution of multiple independent cancer founders from the non-cancer ancestors was common, contributing to intratumour heterogeneity. The number of driver events did not correlate with histology, suggesting the role of local microenvironments and/or epigenetic driver events. A similar evolutionary pattern was also observed in another case evolving from an AKT1-mutated founder. Taken together, our findings provide new insight into how breast cancer evolves.

Chromatin conformational changes at human satellite II contribute to the senescence phenotype in the tumor microenvironment.

Cellular senescence and senescence-associated secretory phenotype (SASP) in stromal cells within the tumor microenvironment promote cancer progression. Although cellular senescence has been shown to induce changes in the higher-order chromatin structure and abnormal transcription of repetitive elements in the genome, the functional significance of these changes is unclear. In this study, we examined the human satellite II (hSATII) loci in the pericentromere to understand these changes and their functional significance. Our results indicated that the hSATII loci decompact during senescence induction, resulting in new DNA-DNA interactions in distinct genomic regions, which we refer to as DRISR (Distinctive Regions Interacted with Satellite II in Replicative senescent Fibroblasts). Interestingly, decompaction occurs before the expression of hSATII RNA. The DRISR with altered chromatin accessibility was enriched for motifs associated with cellular senescence and inflammatory SASP genes. Moreover, DNA-fluorescence in situ hybridization analysis of the breast cancer tissues revealed hSATII decompaction in cancer and stromal cells. Furthermore, we reanalyzed the single-cell assay for transposase-accessible chromatin with sequencing data and found increased SASP-related gene expression in fibroblasts exhibiting hSATII decompaction in breast cancer tissues. These findings suggest that changes in the higher-order chromatin structure of the pericentromeric repetitive sequences during cellular senescence might directly contribute to the cellular senescence phenotype and cancer progression via inflammatory gene expression.

APC/PIK3CA mutations and ß-catenin status predict tankyrase inhibitor sensitivity of patient-derived colorectal cancer cells.

BACKGROUND: Aberrant WNT/ß-catenin signaling drives carcinogenesis. Tankyrases poly(ADP-ribosyl)ate and destabilize AXINs, ß-catenin repressors. Tankyrase inhibitors block WNT/ß-catenin signaling and colorectal cancer (CRC) growth. We previously reported that 'short' APC mutations, lacking all seven ß-catenin-binding 20-amino acid repeats (20-AARs), are potential predictive biomarkers for CRC cell sensitivity to tankyrase inhibitors. Meanwhile, 'Long' APC mutations, which possess more than one 20-AAR, do not predict inhibitor-resistant cells. Thus, additional biomarkers are needed to precisely predict the inhibitor sensitivity. METHODS: Using 47 CRC patient-derived cells (PDCs), we examined correlations between the sensitivity to tankyrase inhibitors (G007-LK and RK-582), driver mutations, and the expressions of signaling factors. NOD.CB17-Prkdcscid/J and BALB/c-nu/nu xenograft mice were treated with RK-582. RESULTS: Short APC mutant CRC cells exhibited high/intermediate sensitivities to tankyrase inhibitors in vitro and in vivo. Active ß-catenin levels correlated with inhibitor sensitivity in both short and long APC mutant PDCs. PIK3CA mutations, but not KRAS/BRAF mutations, were more frequent in inhibitor-resistant PDCs. Some wild-type APC PDCs showed inhibitor sensitivity in a ß-catenin-independent manner. CONCLUSIONS: APC/PIK3CA mutations and ß-catenin predict the sensitivity of APC-mutated CRC PDCs to tankyrase inhibitors. These observations may help inform the strategy of patient selection in future clinical trials of tankyrase inhibitors.

Whole-genome landscape of adult T-cell leukemia/lymphoma.

Adult T-cell leukemia/lymphoma (ATL) is an aggressive neoplasm immunophenotypically resembling regulatory T cells, associated with human T-cell leukemia virus type-1. Here, we performed whole-genome sequencing (WGS) of 150 ATL cases to reveal the overarching landscape of genetic alterations in ATL. We discovered frequent (33%) loss-of-function alterations preferentially targeting the CIC long isoform, which were overlooked by previous exome-centric studies of various cancer types. Long but not short isoform-specific inactivation of Cic selectively increased CD4+CD25+Foxp3+ T cells in vivo. We also found recurrent (13%) 3'-truncations of REL, which induce transcriptional upregulation and generate gain-of-function proteins. More importantly, REL truncations are also common in diffuse large B-cell lymphoma, especially in germinal center B-cell-like subtype (12%). In the non-coding genome, we identified recurrent mutations in regulatory elements, particularly splice sites, of several driver genes. In addition, we characterized the different mutational processes operative in clustered hypermutation sites within and outside immunoglobulin/T-cell receptor genes and identified the mutational enrichment at the binding sites of host and viral transcription factors, suggesting their activities in ATL. By combining the analyses for coding and noncoding mutations, structural variations, and copy number alterations, we discovered 56 recurrently altered driver genes, including 11 novel ones. Finally, ATL cases were classified into 2 molecular groups with distinct clinical and genetic characteristics based on the driver alteration profile. Our findings not only help to improve diagnostic and therapeutic strategies in ATL, but also provide insights into T-cell biology and have implications for genome-wide cancer driver discovery.

Early gastric cancer with RhoGAP fusion is linked to frequent nodal metastasis and a part of microtubular-mucocellular histology.

INTRODUCTION: Gastric cancer with fusion genes involving the Rho GTPase-activating protein domain (RhoGAP-GC) is mainly included in the genomically stable type of The Cancer Genome Atlas classification. Clinical implications and histological characteristics of RhoGAP-GC in the early phase remain unclear. METHODS: We analyzed 878 consecutive pT1b GCs for RhoGAP and its partner genes using fluorescence in situ hybridization assay. RESULTS: RhoGAP fusion was detected in 57 (6.5%) GCs. Univariate analysis revealed that female sex, middle-lower third tumor location, advanced macroscopic type, tumor diameter > 2 cm, pT1b2, lymphatic invasion, venous invasion, negative EBER-ISH, and RhoGAP fusion were significantly associated with lymph node metastasis (LNM). Multivariate analysis presented RhoGAP fusion, lymphatic invasion, tumor diameter > 2 cm, advanced macroscopic type, venous invasion, and middle-lower third tumor location as independent risk factors for LNM. Notably, RhoGAP fusion had the highest odds ratio (3.92) for LNM among analyzed parameters (95% CI 2.12-7.27; p < 0.001). Compared to non-RhoGAP-GCs, RhoGAP-GCs were significantly frequent in younger females and showed the highest incidence of lymphatic invasion (56.2%) and LNM (49.1%) (p < 0.001). Histologically, microtubular architecture with pseudo-trabecular interconnection and small aggregations of tumor cells with a varied amount of cytoplasmic mucin, named "microtubular-mucocellular (MTMC) histology," was found in 93.0% (53 of 57) of RhoGAP-GCs in the intramucosal area. MTMC histology showed high sensitivity and negative predictive value (93.0% and 99.4%, respectively) for RhoGAP fusion, albeit positive predictive value is low (34.9%). CONCLUSION: RhoGAP-GC is linked to a characteristic MTMC histology and a high incidence of LNM.

Potential involvement of oncostatin M in the immunosuppressive tumor immune microenvironment in hepatocellular carcinoma with vessels encapsulating tumor clusters.

AIM: Vessels encapsulating tumor clusters (VETC) represents an adverse prognostic morphological feature of hepatocellular carcinoma (HCC), which is associated with an immunosuppressive tumor immune microenvironment (TIM). However, the underlying factors characterizing the TIM in HCC with a VETC pattern (VETC-positive HCC) remain uncertain. Oncostatin M (OSM), a pleiotropic cytokine of the interleukin-6 family, regulates various biological processes, including inflammation, proliferation, and invasiveness of tumor cells. We aimed to test a hypothesis that OSM is associated with the immunosuppressive TIM of VETC-positive HCC. METHODS: A total of 397 consecutive HCC patients with curative-intent hepatectomy were included. OSM-positive cells and inflammatory cells including CD4-, CD8-, CD163-, and FOXP3-positive cells were immunohistochemically evaluated. We compared VETC-positive and VETC-negative HCCs in terms of the number of these cells. RESULTS: We found the VETC pattern in 62 patients (15.6%). Our analysis revealed a significant decrease in the expression of arginase-1, a marker associated with mature hepatocyte differentiation, in VETC-positive HCC (p = 0.046). The number of tumor-infiltrating OSM-positive cells was significantly low in VETC-positive HCC (p = 0.0057). Notably, in VETC-positive HCC, the number of OSM-positive cells was not associated with vascular invasion, whereas in VETC-negative HCC, an increase in the number of OSM-positive cells was associated with vascular invasion (p = 0.042). CONCLUSIONS: We identified an association between a decrease in OSM-positive cells and the VETC pattern. Additionally, our findings indicate that VETC-positive HCC is characterized by low hepatocyte differentiation and OSM-independent vascular invasion. These findings highlight the potential interaction between VETC-positive HCC cells and their TIM through the reduction of OSM-expressing cells.

Availability of genome-matched therapy based on clinical practice.

BACKGROUND: Comprehensive genomic profiling (CGP) provides new opportunities for patients with advanced cancer to receive genome-matched therapies, but the availability rate of these remains low. We reviewed our CGP cases and suggested possible strategies to improve the current status from a clinical perspective. METHODS: Druggable genomic alterations and barriers to accessing genome-matched therapies were investigated in 653 patients with 30 various types of cancers who underwent CGP. RESULTS: While the availability rate of genome-matched therapies as a whole was 9.5%, CGP was useful in some cancer types. Patients with thyroid cancer and lung cancer harbored druggable genomic alterations at high rates, while sarcoma rarely harbored these alterations (100%, 76%, and 15.2%, respectively). In contrast, the availability rate of genome-matched therapies was highest in patients with sarcoma and head and neck cancer (HNC) (60% and 40%, respectively). One hundred thirteen patients (63.5%) had multiple barriers to accessing genome-matched therapy. Of 178 patients, 21 patients (11.8%) could not be considered for genome-matched therapies solely because of the deterioration of their performance status. CONCLUSION: This study demonstrated the usefulness of CGP for patients with sarcoma and HNC in addition to lung cancer in clinical practice. Performing CGP at the front line has the potential to improve the availability of genome-matched therapy.

Epstein-Barr virus-positive monoclonal lymphoplasmacytic proliferation associated with neurosyphilis in an immunocompetent patient: A case report.

Syphilis is an infectious disease caused by the spirochete bacterium Treponema pallidum. Neurosyphilis results from the infection of the nervous system with Treponema pallidum, which can occur at any stage of syphilis. Neurosyphilis is often overlooked because of its rarity. Early-stage neurosyphilis with brain mass formation is rare. We present a case of early-stage neurosyphilis with prominent Epstein-Barr virus (EBV)-positive monoclonal lymphoplasmacytic proliferation in an immunocompetent patient. A 36-year-old man presented with a chief complaint of a progressively worsening headache, a newly developed skin rash, and a fever. Magnetic resonance imaging showed a mass lesion, which measured 18 mm in diameter, in the left frontal lobe of the cerebrum. The patient underwent an emergency operation to remove the abscess. A pathological investigation revealed complex findings. There was an abscess in the cerebrum. Lymphoplasmacytic meningitis was also noted. In addition, a vaguely nodular lesion, which was composed of plasmacytoid and lymphoid cells, was observed around the abscess. Immunohistochemically, an anti-Treponema pallidum antibody revealed numerous Treponemas around the abscess. In situ hybridization revealed that the plasmacytoid and lymphoid cells were Epstein-Barr encoding region (EBER)-positive; κ-positive cells were significantly more prevalent than λ-positive cells, suggesting light-chain restriction. Postoperatively, parenteral antibiotics were administered for four weeks. The patient has been free of recurrence for two years since the surgery. No association between neurosyphilis and EBV-positive lymphoplasmacytic proliferation has ever been reported. Mass formation in early-stage neurosyphilis is an exceptionally rare event. The present case indicates that in syphilis patients, lymphoproliferative disorders that lead to mass formation may be caused by concomitant EBV reactivation. Furthermore, when treating patients with mass lesions of the central nervous system, it is important to check their medical history and perform laboratory screening for infectious diseases to avoid overlooking syphilis infections.

Prognostic impact of cancer genomic profile testing for advanced or metastatic solid tumors in clinical practice.

Cancer genomic profile (CGP) testing, which is covered by the national health insurance system in Japan, has been introduced as a routine clinical practice. However, the effects of CGP testing on prognoses remain unclear. Drug accessibility rates and prognoses after CGP testing were retrospectively investigated in 713 patients who underwent CGP testing examined by our molecular tumor board between November 2019 and October 2022,. Overall survival (OS) was examined using the log-rank test and the Kaplan-Meier method. The median age of patients (326 males and 387 females) was 58 years (12-85 years). CGP testing revealed one or more gene mutations in 681 cases (95.5%), among which actionable gene mutations were detected in 439 (61.6%). Although treatment options were recommended for 285 cases (40.0%) by the molecular tumor board, only 45 received treatment based on their gene mutations. During the median observation period of 8.6 months, 351 (49.2%) patients died of the exacerbation of existing diseases. No significant differences were observed in OS between patients treated with and without genomically matched therapy (p = 0.285). According to clinical responses to treatment based on gene mutations, median OS was significantly longer in patients who achieved partial response and stable disease (26.5 months; 95% CI 14.4-38.6) than in those with progressive disease and not evaluated (9.8 months; 95% CI 5.8-13.8, p = 0.013). Responses to treatment based on gene mutations may improve prognoses, and it is important to increase the drug accessibility rate after CGP testing.

Spatiotemporal commonality of the TCR repertoire in a T-cell memory murine model and in metastatic human colorectal cancer.

Immune checkpoint inhibitors (ICIs) have shown superior clinical responses and significantly prolong overall survival (OS) for many types of cancer. However, some patients exhibit long-term OS, whereas others do not respond to ICI therapy at all. To develop more effective and long-lasting ICI therapy, understanding the host immune response to tumors and the development of biomarkers are imperative. In this study, we established an MC38 immunological memory mouse model by administering an anti-PD-L1 antibody and evaluating the detailed characteristics of the immune microenvironment including the T cell receptor (TCR) repertoire. In addition, we found that the memory mouse can be established by surgical resection of residual tumor following anti-PD-L1 antibody treatment with a success rate of > 40%. In this model, specific depletion of CD8 T cells revealed that they were responsible for the rejection of reinoculated MC38 cells. Analysis of the tumor microenvironment (TME) of memory mice using RNA-seq and flow cytometry revealed that memory mice had a quick and robust immune response to MC38 cells compared with naïve mice. A TCR repertoire analysis indicated that T cells with a specific TCR repertoire were expanded in the TME, systemically distributed, and preserved in the host for a long time period. We also identified shared TCR clonotypes between serially resected tumors in patients with colorectal cancer (CRC). Our results suggest that memory T cells are widely preserved in patients with CRC, and the MC38 memory model is potentially useful for the analysis of systemic memory T-cell behavior.

Comparison and Development of Immunohistochemical Diagnostic Criteria for Blastic Plasmacytoid Dendritic Cell Neoplasm.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematological malignancy derived from the precursors of plasmacytoid dendritic cells. Diagnostic criteria for BPDCN have not been fully established. BPDCN is often diagnosed without other BPDCN markers than the 3 conventional markers (CD4, CD56, and CD123) in practice and case reports, although acute myeloid leukemia/myeloid sarcoma (AML/MS), which is always considered in the differential diagnosis of BPDCN, can express them. We reviewed published case reports on BPDCN and found that the diagnosis was made without any other BPDCN markers than the conventional markers in two-thirds of the cases. Next, 4 representative existing diagnostic criteria were applied to 284 cases of our cohort of BPDCN and mimics. The results differed in 20% (56/284) of the cases. The criterion based on the 3 conventional markers alone had a low concordance rate (80%-82%) with the other 3 criteria, which were almost concordant with each other. However, newly found minor limitations in these criteria prompted us to devise new diagnostic criterion for BPDCN composed of TCF4, CD123, TCL1, and lysozyme. We also revealed that CD123-positive AML/MS patients had a significantly poorer outcome than those with BPDCN and that 12% (24/205) of the cases were non-BPDCN even if all 3 conventional markers were positive, thus clarifying the risk of diagnosing BPDCN without more specific markers. In addition, histopathological features, such as the reticular pattern, which is not seen in BPDCN and suggests AML/MS, were also identified.

Clinicopathologic and genetic characterization of angiofibroma of soft tissue: a study of 12 cases including two cases with AHRR::NCOA3 gene fusion.

AIMS: Angiofibroma of soft tissue (AFST) is a benign tumour characterised by prominent arborizing blood vessels throughout the lesion. Approximately two-thirds of AFST cases were reported to have AHRR::NCOA2 fusion, and only two cases have been reported to have other gene fusions: GTF2I::NCOA2 or GAB1::ABL1. Although AFST is included in fibroblastic and myofibroblastic tumours in the World Health Organization's 2020 classification, histiocytic markers, especially CD163, have been reported to be positive in almost all examined cases, and it still remains the possibility of a fibrohistiocytic nature of the tumour. Therefore, we aimed to clarify the genetic and pathological spectrum of AFST and identify whether histiocytic marker-positive cells were true neoplastic cells. METHODS AND RESULTS: We evaluated 12 AFST cases, which included 10 cases with AHRR::NCOA2 and two with AHRR::NCOA3 fusions. Pathologically, nuclear palisading, which has not been reported in AFST, was detected in two cases. Furthermore, one tumour resected by additional wide resection revealed severe infiltrative growth. Immunohistochemical analysis indicated varying levels of desmin-positive cells in nine cases, whereas CD163- and CD68-positive cells were diffusely distributed in all 12 cases. We also performed double immunofluorescence staining and immunofluorescence in situ hybridisation in four resected cases with >10% desmin-positive tumour cells. The results suggested that the CD163-positive cells differed from desmin-positive cells with AHRR::NCOA2 fusion in all four cases. CONCLUSION: Our findings suggested that AHRR::NCOA3 could be the second most frequent fusion gene, and histiocytic marker-positive cells are not genuine neoplastic cells in AFST.

Eosinophil-rich variant of nodal marginal zone lymphoma: a clinicopathological study of 11 cases.

AIMS: Tissue eosinophilia is commonly observed in T-cell and classic Hodgkin lymphomas, but rarely in B-cell lymphomas. Herein, we present the first report of a case series on nodal marginal zone lymphoma (NMZL) with tissue eosinophilia. METHODS AND RESULTS: All 11 patients in this study had nodal disease at primary presentation. The mean age at diagnosis was 64 years. The mean follow-up period was 39 months, and all patients were alive. Nine of the 11 patients (82%) showed no recurrence, but the other two patients experienced recurrence in the lymph nodes or skin. Marked eosinophilic infiltration was observed in all biopsied lymph nodes. Nine of the 11 patients had a preserved nodular architecture with expanded interfollicular areas. The other two patients showed diffuse lymphoma cell infiltration with effacement of nodal architecture. One of them was diagnosed as having diffuse large B-cell lymphoma transformed from NMZL because large cells accounted for >50% of the lymphoma cells and formed sheet-like patterns. Cells were positive for CD20 and BCL2 and negative for CD5, CD10, and BCL6. Some patients showed myeloid cell nuclear differentiation antigen (MNDA) positivity. All patients showed B-cell monoclonality via flow cytometry, southern blotting, and/or polymerase chain reaction (PCR). CONCLUSION: All patients showed distinctive morphological features and could be misdiagnosed with peripheral T-cell lymphoma due to their eosinophil-rich backgrounds. The predominance of B cells, absence of histiocytes, and high endothelial venules in the interfollicular areas are key factors for diagnosis. B-cell monoclonality is the most reliable evidence of differentiation. We designated this type of lymphoma as an eosinophil-rich variant of NMZL.

Prognostic factors for primary cutaneous anaplastic large-cell lymphoma: a multicentre retrospective study from Japan.

BACKGROUND: The clinical implications of DUSP22 rearrangement and the association between DUSP22 rearrangement and lymphoid enhancer-binding factor 1 (LEF1) expression pattern in CD30+ cutaneous T-cell lymphomas (CTCLs) are unknown. OBJECTIVES: This study assessed the incidence of DUSP22 rearrangement and its clinical and immunohistochemical implications in primary cutaneous anaplastic large-cell lymphoma (pcALCL), lymphomatoid papulosis (LyP) and CD30+ mycosis fungoides with large-cell transformation (MF-LCT), focusing especially on the association with the prognosis and LEF1 expression pattern. Prognostic factors of pcALCL were also examined. METHODS: We conducted a multicentre retrospective study including patients with pcALCL, LyP and MF-LCT diagnosed between 1 January 2000 and 31 December 2018 in Japan. Baseline data at diagnosis, treatment course, overall survival (OS) and disease-specific survival (DSS) were collected. Immunohistochemical analysis and fluorescence in situ hybridization to detect DUSP22 and TP63 rearrangement were performed using skin samples at diagnosis. We investigated the association between staining pattern and these gene rearrangements. We also assessed the prognostic implications of clinical status, immunohistochemical results and the presence of gene rearrangements. RESULTS: DUSP22 rearrangement was detected in 50% (11 of 22) of cases of pcALCL, but not in any cases with LyP (0 of 14) or MF-LCT (0 of 11). TP63 rearrangement was not detected in any case. Clinically, patients with pcALCL with DUSP22 rearrangement did not tend to develop ulcers (P = 0.081). There was no significant association between DUSP22 rearrangement status and immunohistochemical results, including LEF1 expression pattern. T3 stage and the presence of lower limb lesions were significantly associated with shorter OS (P = 0.012 and 0.021, respectively, by log-rank test). Similarly, they were significantly correlated with shorter DSS (P = 0.016 and 0.0001, respectively). CONCLUSIONS: DUSP22 rearrangement is relatively specific to pcALCL among CD30+ CTCLs in Japan. Although the LEF1 expression pattern was not related to DUSP22 rearrangement in pcALCL, there was no rearrangement if LEF1 was not expressed. We confirmed that T3 stage and the lower limb involvement were significantly associated with decreased OS and DSS. The presence or absence of lower limb lesions should be included in T-stage subcategorization in the future.

Long-Term Outcomes After Lobectomy for Patients with High-Risk Papillary Thyroid Carcinoma.

BACKGROUND: Guidelines universally recommend total thyroidectomy for high-risk papillary thyroid carcinoma (PTC). However, in Japan, thyroid-conserving surgery had been widely applied for such patients until recently. We investigated long-term outcomes for this strategy. METHODS: A prospectively recorded database was retrospectively analyzed for 368 patients who had undergone curative surgery for high-risk PTC without distant metastasis between 1993 and 2013. High-risk PTC was defined for tumors showing tumor size > 4 cm, extrathyroidal extension, or large nodal metastasis ≥ 3 cm. RESULTS: Median age was 59 years and 243 patients were female. Mean duration of follow-up was 12.7 years. Lobectomy was conducted for 207 patients (LT group) and total or near-total thyroidectomy for 161 patients (TT group). The frequency of massive extrathyroidal invasion and large nodal metastasis was lower in the LT group than in the TT group. After propensity score matching, no significant differences were seen between groups for overall survival, cause-specific survival or distant recurrence-free survival. In the overall cohort, multivariate analysis identified age ≥ 55 years, large nodal metastasis, tumor size > 4 cm and massive extrathyroidal invasion as significantly associated with cause-specific survival, whereas extent of thyroidectomy was not. CONCLUSIONS: For patients with high-risk PTC without distant metastasis, curative surgery with lobectomy showed almost identical oncological outcomes compared to total thyroidectomy. The benefits of total thyroidectomy for high-risk PTC should be reevaluated in the future prospective studies.

Constant small-cell changes and variable LEF1 expression in DUSP22-rearranged primary cutaneous anaplastic large-cell lymphoma: Analysis of the repeated biopsies of three patients.

DUSP22-rearranged primary cutaneous anaplastic large-cell lymphoma (pcALCL) has a biphasic histological pattern defined by large dermal atypical lymphocytes and epidermotropic small lymphocytes resembling pagetoid reticulosis, but the positivity rate of the biphasic pattern in DUSP22-rearranged pcALCL is unknown. Immunohistochemically, LEF1 expression in >75% of tumor cells is associated with DUSP22-rearrangement (DUSP22-R) in systemic ALCL. However, whether this association applies to pcALCL remains unclear. To analyze these pathological clues for screening DUSP22-R, we reviewed 11 skin biopsies from three patients with DUSP22-rearranged pcALCL. All specimens showed a biphasic pattern, of which three showed nonpagetoid infiltration of the epidermis. In all lesions, small-cell changes of tumor cells were observed not only within the epidermis but also under the epidermis. LEF1 positivity rates varied by lesion (range: 30%-90%, mean: 59.6%) with only three patients expressing LEF1 in more than 75% of tumor cells. In conclusion, the biphasic pattern was a constant finding in DUSP22-rearranged pcALCL, but it was not always pagetoid reticulosis-like. The recognition of small-cell change outside the epidermis may be helpful in diagnosing DUSP22-rearranged pcALCL. However, LEF1 expression was variable and its diagnostic usefulness may be limited.

Estrogen Receptor-ß Gene Cytosine-Adenine (ESR2-CA) Repeat Polymorphism in Postmenopausal Colon Cancer.

The pathobiological role of estrogen is controversial in colorectal cancer. Cytosine-adenine (CA) repeat in the estrogen receptor (ER)-ß gene (ESR2-CA) is a microsatellite, as well as representative of ESR2 polymorphism. Though its function is unknown, we previously showed that a shorter allele (germline) increased the risk of colon cancer in older women, whereas it decreased it in younger postmenopausal women. ESR2-CA and ER-ß expressions were examined in cancerous (Ca) and non-cancerous (NonCa) tissue pairs from 114 postmenopausal women, and comparisons were made considering tissue types, age/locus, and the mismatch repair protein (MMR) status. ESR2-CA repeats <22/≥22 were designated as 'S'/'L', respectively, resulting in genotypes SS/nSS (=SL&LL). In NonCa, the rate of the SS genotype and ER-ß expression level were significantly higher in right-sided cases of women ≥70 (≥70Rt) than in those in the others. A decreased ER-ß expression in Ca compared with NonCa was observed in proficient-MMR, but not in deficient-MMR. In NonCa, but not in Ca, ER-ß expression was significantly higher in SS than in nSS. ≥70Rt cases were characterized by NonCa with a high rate of SS genotype or high ER-ß expression. The germline ESR2-CA genotype and resulting ER-ß expression were considered to affect the clinical characteristics (age/locus/MMR status) of colon cancer, supporting our previous findings.

Profiling chromosomal-level variations in gastric malignancies.

Aneuploidy arises from persistent chromosome segregation errors, or chromosomal instability. Although it has long been known as a hallmark of cancer cells, reduced cellular fitness upon induced ploidy alterations hinders the understanding of how aneuploidy relates to cancer development in the body. In this study, we used FISH analysis targeting centromeres to indicate ploidy changes, and quantitatively evaluated the ploidy statuses of gastric tumors derived from a total of 214 patients, ranging from early to advanced disease. We found that cancer cells reveal a marked elevation of aneuploid population, increasingly in cases diagnosed in advanced stages. The expansion of the aneuploid population is well associated with p53 deficiency, consistent with its essential role in genome maintenance. Comparisons among multiple locations within the tumor, or between the primary and metastatic tumors, indicated that cancer cells mostly retain their ploidy alterations throughout primary tumors, but metastatic tumors may consist of cells with either increased or decreased levels of aneuploidy. We also found that a notable proportion of polyploid cells are often already present in chronic gastritis epithelia. These observations underscore that chromosome-level variations are widespread in gastric cancers, shaping their genetic heterogeneity and malignant properties.

High prevalence of TERT aberrations in myxoid liposarcoma: TERT reactivation may play a crucial role in tumorigenesis.

Myxoid liposarcoma (MLPS) is genetically characterized by FUS-DDIT3 or EWSR1-DDIT3 gene fusion and the high frequency of hotspot mutations (C228T or C250T) in the promoter region of telomerase reverse transcriptase (TERT) that encodes the TERT protein. The latter leads to telomerase reactivation, a mechanism of telomere maintenance. Although the TERT promoter hotspot mutation is a poor prognostic factor in various tumors, its effect on MLPS has not been reported in detail. In the present study, we examined the clinicopathological characteristics, prognosis, and telomere maintenance mechanisms in 83 primary tumor samples of MLPS, which were resected surgically at the Cancer Institute Hospital, Japanese Foundation for Cancer Research, Tokyo, Japan, from 2008 to 2020. TERT promoter hotspot mutations were observed in 77% (63/82) cases, and alternative lengthening of telomeres (ALT) was absent in all cases. Among the cases without TERT promoter hotspot mutations, TERT rearrangements, and minor point mutations in the TERT promoter region were found in 3 and 2 cases, respectively. TERT mRNA expression was observed consistently even in patients for whom no genomic TERT aberrations were detected, and the presence of TERT promoter hotspot mutation did not correlate significantly with either overall and metastasis-free survival (P = .56, P = .83, respectively) or clinicopathological features. Therefore, patients with MLPS characteristically shows TERT expression and a high prevalence of TERT aberrations. Our findings suggest that TERT aberration is not prognostic factor, but might occur at an early stage and play a key role in tumorigenesis.

The ELEANOR noncoding RNA expression contributes to cancer dormancy and predicts late recurrence of estrogen receptor-positive breast cancer.

The recurrence risk of estrogen receptor (ER)-positive breast cancer remains high for a long period of time, unlike other types of cancer. Late recurrence reflects the ability of cancer cells to remain dormant through various events, including cancer stemness acquisition, but the detailed mechanism is unknown. ESR1 locus enhancing and activating noncoding RNAs (ELEANORS) are a cluster of nuclear noncoding RNAs originally identified in a recurrent breast cancer cell model. Although their functions as chromatin regulators in vitro are well characterized, their roles in vivo remain elusive. In this study, we evaluated the clinicopathologic features of ELEANORS, using primary and corresponding metastatic breast cancer tissues. The ELEANOR expression was restricted to ER-positive cases and well-correlated with the ER and progesterone receptor expression levels, especially at the metastatic sites. ELEANORS were detected in both primary and metastatic tumors (32% and 29%, respectively), and frequently in postmenopausal cases. Interestingly, after surgery, patients with ELEANOR-positive primary tumors showed increased relapse rates after, but not within, 5 years. Multivariate analysis showed that ELEANORS are an independent recurrence risk factor. Consistently, analyses with cell lines, mouse xenografts, and patient tissues revealed that ELEANORS upregulate a breast cancer stemness gene, CD44, and maintain the cancer stem cell population, which could facilitate tumor dormancy. Our findings highlight a new role of nuclear long noncoding RNAs and their clinical potential as predictive biomarkers and therapeutic targets for late recurrence of ER-positive breast cancer.