Abstract 4902: Clonal evolution of proliferative lesions into breast cancers

[Introduction] Proliferative lesions in the breast have been implicated in the development of invasive breast cancer. Previous studies showed that adjacent atypical proliferative lesions and breast cancers shared common genetic alterations, suggesting that these evolved from the same ancestral cell. However, the clonal structure of atypical proliferative lesions and their clonal dynamics during progression to cancer are poorly understood. In this study, we compared genetic profiles of proliferative lesions and cancers from the same patients to illustrate the clonal evolution of cancer from a non-malignant epithelial cell.

[Methods] Multiple samples were collected from various lesions with different disease-level located in the cancer-borne breast, using micro-dissection from formalin-fixed, paraffin-embedded surgical specimens. Somatic mutations and copy number alterations (CNAs) were evaluated by whole exome sequencing.

[Results] A total of 39 samples from 6 premenopausal females carrying estrogen receptor-positive cancers were analyzed, where the samples were obtained from non-atypical (N = 1) and atypical (N = 8) proliferative lesions, and non-invasive (N = 21) and invasive (N = 4) cancers. The number of somatic mutations per sample increased with disease progression (ranging from 2 to 311). Two cases with bilateral cancers had a pathogenic germline mutation of either BRCA2 or TP53, where no somatic mutations or CNAs were shared by individual proliferative lesions, suggesting multifocal independent cancerous evolutions. By contrast, in the remaining four unilateral cases, no pathogenic germline mutations were detected, but all proliferative lesions, which were separated by a distance of 7 - 70 mm, shared one or more driver alterations, such as an AKT1 mutation, a GATA3 mutation, a CBFB mutation and concurrent 1q gain and 16q loss, while harboring private mutations/CNAs of their own. The analysis of phylogenic trees based on the number of shared mutations predicted an early origin of these founder mutations, which frequently predated decades before the onset of cancer.

[Conclusions] Our results suggest that early breast cancer development is shaped by the evolution of multiple precancerous clones. In hereditary cases, this process is thought to be substantially promoted multi-focally within the entire breasts, due to innate genomic instability in each mammary epithelial cell for pathogenic germline mutations. By contrast, in sporadic cases, the ancestral cell which has acquired a founder genetic alteration expands macroscopically long before the onset of cancer, most likely in early adolescent. These expanded clones work as the niche predisposed to additional mutations, in which branching evolution occurs multi-focally and raises up multiple proliferative lesions, from which invasive cancer finally evolves. Our findings provide unique insight into the early development of breast cancer.

Citation Format: Tomomi Nishimura, Nobuyuki Kakiuchi, Kenichi Yoshida, Yasuhide Takeuchi, Hirona Maeda, Yusuke Shiozawa, Masahiro M. Nakagawa, Yotaro Ochi, Yukiko Kawata, Kosuke Aoki, Masahiro Hirata, Tatsuki R. Kataoka, Takaki Sakurai, Satoko Baba, Yuichi Shiraishi, Kenichi Chiba, Kengo Takeuchi, Hironori Haga, Satoru Miyano, Masakazu Toi, Seishi Ogawa. Clonal evolution of proliferative lesions into breast cancers [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4902.

Improvement of microcirculatory impairment in patients with predialysis chronic kidney disease after AST-120 administration

Background

Endothelial dysfunction starts at an earlier stage in patients with chronic kidney disease (CKD), and induces macro- and microcirculatory impairments. We evaluated whether uremic toxin-lowering therapy could improve endothelial function in patients with CKD.

Methods

We performed a prospective interventional trial with 30 predialysis non-diabetic CKD patients who were administered oral adsorbent AST-120 (6 g/day) for 12 months. Surrogate markers of endothelial function including flow-mediated dilation (FMD) and skin perfusion pressure (SPP) were serially evaluated along with serum indoxyl sulfate (IS) levels and renal function. Renal function was evaluated based on blood urea nitrogen, serum creatinine (sCr) levels, and estimated glomerular filtration ratio (eGFR).

Results

Monthly decline in renal function (slope of reciprocal sCr) after AST-120 administration did not change compared to that during the pre-treatment period. However, serum IS levels significantly decreased at 3 months after AST-120 administration (p < 0.01), and it was sustained during the period of AST-120 administration (p < 0.01). Although FMD did not improve, SPP was constantly elevated after AST-120 administration, and was significantly higher at 12 months compared with baseline value (69.7 ± 14.6 vs. 78.8 ± 18.9 mmHg, p < 0.05). A significant correlation between the change of IS and SPP from baseline values was shown at 6 months after AST-120 administration (r = − 0.558, p = 0.02).

Conclusion

Microcirculatory impairment was improved after AST-120 administration in patients with predialysis CKD.

Trial registration

UMIN, UMIN000013577. Registered on March 31, 2014,

Antihypertensive drug telmisartan suppresses the proliferation of gastric cancer cells in vitro and in vivo

Gastric cancer is one of the most common malignancies diagnosed worldwide. Telmisartan, an angiotensin receptor blocker (ARB), suppresses the proliferation of cancer cells and the growth of tumors through an unknown mechanism. To identify the mechanism, the present study was designed to evaluate the effects of telmisartan on gastric cancer cell lines and tumors in vitro and in vivo and the associated signaling molecules were identified. It was shown here that telmisartan suppressed the proliferation of the cultured human gastric cancer cell lines MKN74, MKN1 and MKN45 as detected in the CCK‑8 assay. In a mouse xenograft model of gastric cancer, telmisartan suppressed tumor growth by arresting the cell cycle at the G0/G1 phase through inhibition of the expression of cyclin D1, the catalytic subunit of cyclin dependent kinase 4 (CDK4), as well as the phosphorylation of the tumor suppressor retinoblastoma (pRb) protein as detected by western blotting. Notably, telmisartan did not induce apoptosis, as indicated by consistent levels of caspase‑cleaved keratin 18 in MKN74 cells. Furthermore, telmisartan inhibited the phosphorylation of epidermal growth factor receptor (EGFR) and increased the levels of the angiogenesis‑related protein tissue inhibitor of metalloproteinase‑1 (TIMP‑1). Analyses of microarrays revealed that telmisartan altered the expression of miRNAs in MKN74 cells. In conclusion, telmisartan suppressed the proliferation of human gastric cancer cells by inducing cell cycle arrest.

In vitro Development of Zona Pellucida-free Porcine Zygotes Cultured Individually after Vitrification

BACKGROUND

Cryopreservation of zona pellucida (ZP)-free embryos provides more options for somatic cell nuclear transfer, particularly during handmade cloning.

OBJECTIVE

This study investigated whether the removal of the ZP affects the development of porcine zygotes after vitrification and warming.

MATERIALS AND METHODS

We determined the appropriate volume of the corresponding medium for the individual culture of ZP-intact and -free embryos and evaluated the protection effect of ZP during cryopreservation on the resulting development of the vitrified-warmed zygotes.

RESULTS

The volume of culture medium influenced the development of ZP-intact zygotes, and a volume of 15 µL was most suitable for their development. However, the volume of culture medium did not modify the development of ZP-free zygotes. The removal of the ZP before vitrification did not adversely affect embryonic development or quality of the resulting blastocysts.

CONCLUSION

Our results suggest that the removal of the ZP does not cause detrimental effects to the development of vitrified-warmed zygotes.

Abstract P4-05-15: Clonal evolution of proliferative lesions into breast cancers

[Introduction] Proliferative lesions in the breast have been implicated in the development of invasive breast cancer. Previous studies showed that atypical proliferative lesions and adjacent breast cancers shared common genetic alterations, suggesting that these evolved from the same ancestral cell. However, the clonal structure of atypical proliferative lesions and their clonal dynamics during progression to cancer are poorly understood. In this study, we compared genetic profiles of proliferative lesions and cancer tissues from the same patients to illustrate the clonal evolution of cancer from a non-malignant epithelial cell. [Methods] Multiple samples were collected from various lesions with different disease-level located in the cancer-borne breast, including invasive cancers, using micro-dissection from formalin-fixed, paraffin-embedded surgical specimens. Somatic mutations and copy number alterations (CNAs) were then evaluated by whole exome sequencing. [Results] We analyzed a total of 39 samples from 6 premenopausal females carrying estrogen receptor-positive cancers, where the samples were obtained from non-atypical (N = 1) and atypical (N = 8) proliferative lesions, and non-invasive (N = 21) and invasive (N = 4) cancers. The number of somatic mutations per sample ranged from 2 to 311 and increased with disease progression. Two cases with bilateral cancers had a pathogenic germline mutation of either BRCA2 or TP53, where no somatic mutations or CNAs were shared by individual proliferative lesions, suggesting multifocal independent cancerous evolutions. By contrast, in the remaining four unilateral cases, no pathogenic germline mutations were detected, but all proliferative lesions and cancers, which were separated by a distance of 7- 33 mm, shared one or more driver alterations, such as an AKT1 mutation (UID: KU01), a GATA3 mutation (UID: KU03 and KU06), a CBFB mutation (UID: KU06) and concurrent 1q gain and 16q loss (UID: KU02, KU03 and KU06), while harboring private mutations/CNAs of their own. The phylogenetic analysis based on the number of shared mutations predicted an early origin of these founder genetic alterations, which frequently predated decades before the onset of cancer. [Conclusions] Our results suggest that early breast cancer development is shaped by the evolution of multiple precancerous clones. In hereditary cases, this process is thought to be substantially promoted multi-focally within the entire breasts, due to innate genomic instability in each mammary epithelial cell for pathogenic germline mutations. By contrast, in sporadic cases, the ancestral cell which has acquired a founder genetic alteration expands macroscopically long before the onset of cancer, most likely in early adolescent. These expanded clones work as the niche predisposed to additional mutations, in which branching evolution occurs multi-focally and raises up multiple proliferative lesions, from which invasive cancer finally evolves. Our findings provide unique insight into the early development of breast cancer.

Citation Format: Tomomi Nishimura, Kenichi Yoshida, Nobuyuki Kakiuchi, Yasuhide Takeuchi, Yukiko Kawata, Hirona Maeda, Yusuke Shiozawa, Kosuke Aoki, Masahiro Hirata, Tatsuki R Kataoka, Takaki Sakurai, Satoko Baba, Yuichi Shiraishi, Kenichi Chiba, Kengo Takeuchi, Hironori Haga, Satoru Miyano, Masakazu Toi, Seishi Ogawa. Clonal evolution of proliferative lesions into breast cancers [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P4-05-15.

Variable indoleamine 2,3-dioxygenase expression in acral/mucosal melanoma and its possible link to immunotherapy

Immune checkpoint inhibitors have improved the prognosis of advanced melanoma. Although anti-programmed death ligand-1 (PD-L1) is a well-studied biomarker for response to anti-programmed death-1 PD-1 therapy in melanoma, its clinical relevance remains unclear. It has been established that the high expression of indoleamine 2,3-dioxygenase (IDO) is correlated to a response to anti-CTLA-4 treatment in melanoma. However, it is still unknown whether the IDO expression is associated with response to anti-PD-1 therapy in advanced melanoma. In addition, acral and mucosal melanomas, which comprise a great proportion of all melanomas in Asians, are genetically different subtypes from cutaneous melanomas; however, they have not been independently analyzed due to their low frequency in Western countries. To evaluate the association of IDO and PD-L1 expression with response to anti-PD-1 antibody in acral and mucosal melanoma patients, we analyzed 32 Japanese patients with acral and mucosal melanomas treated with anti-PD-1 antibody from the perspective of IDO and PD-L1 expression levels by immunohistochemistry (IHC). Multivariate Cox regression models showed that the low expression of IDO in tumors was associated with poor progression-free survival (HR = 0.33, 95% CI = 0.13-0.81, P = 0.016), whereas PD-L1 expression on tumors was not associated with progression-free survival. Significantly lower expression of IDO in tumors was found in non-responders compared to responders. Assessment of the IDO expression could be useful for the identification of suitable candidates for anti-PD-1 therapy among acral and mucosal melanomas patients. Further validation study is needed to estimate the clinical utility of our findings.

Abstract 2120: Human epidermal growth factor receptor 3 might be a targetable molecule for treatment of chemotherapy resistant breast cancer

Introduction: Disease control of chemotherapy refractory breast cancer patients (CRBC), who do not respond to conventional treatment strategies, is important. In the setting of neoadjuvant chemotherapy (NAC), susceptibility of the chemotherapeutic agents could be confirmed with clinical relevance. Doxorubicin, docetaxel and paclitaxel have been used as conventional NAC. Eribulin and platinum may also be added in the future. When the drug sensitivity is evaluated by NAC and it is not sensitive to the drugs, there is currently no effective therapy expected to be improved. This is one of the recent unmet medical needs in breast cancer treatment strategy. Materials and Methods: In this study, in order to establish a novel therapeutic strategy for CRBC, we established chemotherapy resistant breast cancer cell lines against doxorubicin, paclitaxel, docetaxel and eribulin using BT549, Hs578t, MDA-MB231, MDA-MB468, and HCC70. We evaluated human epidermal growth factor receptor 3 (HER3) expression in these parental and resistant cell lines. We used U3-1402 (a novel anti-HER3 antibody-drug conjugate) to test if HER3 targeting treatment inhibits the cell proliferation of the chemotherapy resistant cell line with positive conversion of HER3 expression. Results: We found that the change to positive expression of HER3 in paclitaxel resistant BT549 cell line (BT549/PTX) and eribulin resistant Hs578t cell line (Hs578t/ERI) while these two cell lines initially showed negative expression of HER3. In the cell proliferation assay, as we expected, there was no inhibition of proliferation by treatment with HER3 targeting antibody agent U3-1402 in these two cell lines. However, BT549/PTX and Hs578t/ERI with positive conversion of HER3 expression were clearly inhibited their cell proliferation by treatment with U3-1402. Conclusions: It suggests that even in cases whose tumor does not express HER3 initially and show no response for chemotherapy in the NAC, U3-1402 could be effective for the patients with positive conversion of HER3 expression after NAC. We are studying for the role of positive conversion of HER3 expression in the process of acquired chemo-resistance and the elucidation of the molecular mechanism of positive conversion of HER3 expression in these unique treatment condition.

Citation Format: Takeshi Kotake, Eiji Suzuki, Fengling Pu, Tatsuki Kataoka, Masahiro Hirata, Eri Hohokabe, Masakazu Toi. Human epidermal growth factor receptor 3 might be a targetable molecule for treatment of chemotherapy resistant breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2120.

Abstract 741: Clonal evolution of non-malignant proliferative lesions into breast cancers

[Introduction] Non-malignant proliferative lesions in the breast have been implicated in the development of invasive breast cancer. Previous studies showed that adjacent atypical proliferative lesions and breast cancers shared common genetic alterations, suggesting that these evolved from the same ancestral cell. However, the clonal structure of atypical proliferative lesions and their clonal dynamics during progression to cancer are poorly understood. In this study, we compared genetic profiles of normal ducts, non-malignant proliferative lesions and cancers in the same patients to illustrate the clonal evolution of cancer from a non-malignant epithelial cell.

[Methods] Multiple samples were collected from different proliferative lesions within the cancer-borne breast, including invasive cancers, using micro-dissection from formalin-fixed, paraffin-embedded surgical specimens. Somatic mutations and copy number alterations (CNAs) were then evaluated by whole exome sequencing.

[Results] A total of 39 samples from 6 premenopausal females carrying estrogen receptor-positive cancers were analyzed, where the samples were obtained from normal ducts (N = 5), non-malignant proliferative lesions (N = 9), and non-invasive (N = 21) and invasive (N = 4) cancers. The number of somatic mutations per sample was ranging from 1 to 311 and increased with pathological disease progression. Two cases with bilateral cancers had a pathogenic germline mutation of either BRCA2 or TP53, where no somatic mutations or CNAs were shared by individual proliferative lesions, suggesting multifocal independent cancerous evolutions. By contrast, in the remaining four unilateral cases, no pathogenic germline mutations were detected, but all proliferative lesions, which were separated by a distance of 7-33 mm, shared one or more driver alterations, such as an AKT1 mutation (UID: KU01), a GATA3 mutation (UID: KU03 and KU06), a CBFB mutation (UID: KU06) and concurrent 1q gain and 16q loss (UID: KU02, KU03 and KU06), while harboring private mutations/CNAs of their own. The analysis of phylogenic trees based on the number of shared mutations predicted an early origin of these founder mutations, which frequently predated decades before the onset of cancer.

[Conclusions] Early breast cancer development is thought to be shaped by a simultaneous evolution of multiple precancerous clones. It may be multi-focally initiated by a germline mutation, frequently terminated in bilateral cancers. By contrast, in unilateral cases, cancer clones might be derived from a common ancestral clone, which has acquired a driver founder mutation long before the onset of cancer, and undergo independent evolution, giving rise to multiple proliferative lesions, from which invasive cancer finally evolves. Our findings provide unique insight into the early development of breast cancer.

Citation Format: Tomomi Nishimura, Kenichi Yoshida, Yukiko Kawata, Yasuhide Takeuchi, Nobuyuki Kakiuchi, Yusuke Shiozawa, Kosuke Aoki, Masahiro Hirata, Tatsuki R. Kataoka, Takaki Sakurai, Satoko Baba, Yuichi Shiraishi, Kenichi Chiba, Kengo Takeuchi, Hironori Haga, Satoru Miyano, Masakazu Toi, Seishi Ogawa. Clonal evolution of non-malignant proliferative lesions into breast cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 741.

SLAM family member 8 is involved in oncogenic KIT-mediated signalling in human mastocytosis

The signalling lymphocytic activation molecule family member 8 (SLAMF8)/CD353 is a member of the CD2 family of proteins. Its ligand has not been identified. SLAMF8 is expressed by macrophages and suppresses cellular functions. No study has yet explored SLAMF8 expression or function in human mastocytosis, which features oncogenic KIT-mediated proliferation of human mast cells. SLAMF8 protein was expressed in human mastocytosis cells, immunohistochemically. SLAMF8 expression was also evident in the human mast cell lines, HMC1.2 (expressing oncogenic KIT) and LAD2 (expressing wild-type KIT) cells. SLAMF8 knock-down significantly reduced the KIT-mediated growth of HMC1.2 cells but not that of LAD2 cells. SLAMF8 knock-down HMC1.2 cells exhibited significant attenuation of SHP-2 activation and oncogenic KIT-mediated RAS-RAF-ERK signalling. An interaction between SLAMF8 and SHP-2 was confirmed in HMC1.2 cells and all pathological mastocytosis specimens examined (19 of 19 cases, 100%). Thus, SLAMF8 is involved in oncogenic KIT-mediated RAS-RAF-ERK signalling and the subsequent growth of human neoplastic mast cells mediated by SHP-2. SLAMF8 is a possible therapeutic target in human mastocytosis patients.

Alteration of specific cytokine expression patterns in patients with breast cancer

Systemic inflammation has been associated with aggressive tumor growth, invasion, and metastasis. Here we performed a comprehensive analysis of 26 kinds of inflammatory cytokine expression patterns among 185 patients with breast cancer and 54 healthy volunteers followed by chemometric analysis. We identified the specific cytokine expression patterns of breast cancer patients compared to healthy volunteers with (1) VEGF, IL-9, GM-CSF, IL-13, IL-4, and IFNγ, (2) IL-8, IL-10, IL-12, IL-5, IL-7, IL-1α, GCSF, IL-1β, and TNFα and (3) IL-2, Eotaxin, MIP1β, MIP1α, IL-17, and bFGF. Among the patients with breast cancer, we identified the specific cytokine signature of metastatic patients compared to non-metastatic patients. We also established a mathematical model for distinguishing patients with breast cancer from healthy volunteers and metastatic patients from non-metastatic patients. This cytokine network analysis could provide new insights into early intervention and effective therapeutic strategy for patients with breast cancer.

Abstract P3-06-04: Clonal evolution of non-malignant proliferative lesions into breast cancers

[Introduction] Non-malignant proliferative lesions in the breast have been implicated in the development of invasive breast cancer. Previous studies showed that adjacent atypical proliferative lesions and breast cancers shared common genetic alterations, suggesting that these evolved from the same ancestral cell. However, the clonal structure of atypical proliferative lesions and their clonal dynamics during progression to cancer are poorly understood. In this study, we compared genetic profiles (with and without pathogenic germline mutations) of normal mammary ducts, non-malignant proliferative lesions, and cancer tissues from the same patients to illustrate the clonal evolution of cancer from a non-malignant epithelial cell.

[Methods] Multiple samples were collected from different proliferative lesions within the cancer-borne breast, including invasive cancers, using micro-dissection from formalin-fixed, paraffin-embedded surgical specimens. Somatic mutations and copy number alterations (CNAs) were then evaluated by whole exome sequencing.

[Results] We analyzed a total of 34 samples from 5 premenopausal females carrying estrogen receptor-positive cancers, where the samples were obtained from normal ducts (N = 6), non-atypical (N = 1) and atypical (N = 8) proliferative lesions, and non-invasive (N = 16) and invasive (N = 3) cancers. The number of somatic mutations per sample ranged from 1 to 276 and increased with disease progression, regardless of the germline mutation status. Two cases with bilateral cancers had a pathogenic germline mutation of either BRCA2 or TP53, where no somatic mutations or CNAs were shared by individual proliferative lesions, suggesting multifocal independent cancerous evolutions. By contrast, in the remaining three unilateral cases, no pathogenic germline mutations were detected, but all proliferative lesions, which were separated by a distance of 7-25 mm, shared one or more driver alterations, such as an AKT1 mutation (UID: KU01), concurrent 1q gain and 16q loss (der(1;16)) (UID: KU02), and a GATA3 mutation and der(1;16) (UID: KU03), while harboring private mutations and/or CNAs of their own. The phylogenetic analysis based on the number of shared mutations predicted an early origin of these founder mutations, which frequently predated decades before the onset of cancer.

[Conclusions] Our results suggest that early breast cancer development is shaped by the evolution of multiple precancerous clones. These clones are originated from a common ancestor that acquired a founder mutation long before the onset of cancer, followed by branching evolution of multiple clones that acquired additional driver mutations of their own, from which an invasive cancer ultimately develops. In hereditary cases, this process is thought to be substantially promoted multi-focally from within the entire breasts by a germline mutation shared by all mammary cells, frequently resulting in bilateral and/or multifocal breast cancers. Our findings provide unique insight into the early development of breast cancer.

Citation Format: Nishimura T, Yoshida K, Kawata Y, Takeuchi Y, Kakiuchi N, Shiozawa Y, Aoki K, Hirata M, Kataoka TR, Sakurai T, Baba S, Shiraishi Y, Chiba K, Takeuchi K, Haga H, Miyano S, Toi M, Ogawa S. Clonal evolution of non-malignant proliferative lesions into breast cancers [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-06-04.

Abstract 3389: Clonal evolution of atypical proliferative lesions into breast cancers

[Introduction] Non-malignant proliferative lesions in the breast have been implicated in the development of invasive breast cancer. Previous studies showed that adjacent atypical proliferative lesions and breast cancers shared common genetic alterations, suggesting that these evolved from the same ancestral cell. However, the clonal structure of atypical proliferative lesions and their clonal dynamics during progression to cancer are poorly understood. In this study, we compared genetic profiles of normal ducts, non-malignant proliferative lesions and cancers in the same patients to illustrate the clonal evolution of cancer from a non-malignant epithelial cell.

[Methods] Multiple samples were collected from different atypical proliferative lesions within the cancer-borne breast, including invasive cancers, using micro-dissection from formalin-fixed, paraffin-embedded surgical specimens. Somatic mutations and copy number alterations (CNAs) were then evaluated by whole exome sequencing.

[Results] A total of 34 samples from 5 premenopausal females carrying estrogen receptor-positive cancers were analyzed, where the samples were obtained from normal ducts (N = 6), non-atypical (N = 1) and atypical (N = 8) proliferative lesions, and invasive (N = 3) and non-invasive (N = 16) cancers. The number of somatic mutations per sample was ranging from 1 to 276 and increased with an elevation of atypical-level. Two cases with bilateral cancers had a pathogenic germline mutation of either BRCA2 and TP53, where no somatic mutations or CNAs were shared by individual proliferative lesions, suggesting multifocal independent cancerous evolutions. By contrast, in the remaining three unilateral cases, no pathogenic germline mutations were detected, but all proliferative lesions, which were separated by a distance of 7-25 mm, shared one or more driver alterations, such as an AKT1 mutation (UID: KU01), concurrent 1q gain and 16q loss (der(1;16)) (UID: KU02), and a GATA3 mutation and der(1;16) (UID: KU03), while harboring private mutations/CNAs of their own. The analysis of phylogenic trees based on the number of shared mutations predicted an early origin of these founder mutations, which frequently predated decades before the onset of cancer.

[Conclusions] Early breast cancer development is thought to be shaped by the simultaneous evolution of multiple precancerous clones. It may be multi-focally initiated by a germline mutation, frequently terminated in bilateral cancers. Otherwise, in unilateral cases, cancer clones might be derived from a common ancestral clone, which has acquired a driver founder mutation long before the onset of cancer, and undergo independent evolution, giving rise to multiple proliferative lesions, from which invasive cancer finally evolves. Our findings provide unique insight into the early development of breast cancer.

Citation Format: Tomomi Nishimura, Kenichi Yoshida, Yukiko Kawata, Yasuhide Takeuchi, Nobuyuki Kakiuchi, Yusuke Shiozawa, Kosuke Aoki, Masahiro Hirata, Tatsuki R. Kataoka, Takaki Sakurai, Yuichi Shiraishi, Kenichi Chiba, Kengo Takeuchi, Hironori Haga, Satoru Miyano, Masakazu Toi, Seishi Ogawa. Clonal evolution of atypical proliferative lesions into breast cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3389.

Analysis of possible structures of inducible skin-associated lymphoid tissue in lupus erythematosus profundus

Lupus erythematosus profundus (LEP) is a variant of lupus erythematosus, involving the deep dermis and subcutaneous fat. LEP is characterized by the presence of lymphoid follicles (LF) and germinal centers (GC). However, it remains unknown whether these lymphoid structures correspond to the lymphoid tissues such as cutaneous tertiary lymphoid organs (TLO). Previously, we identified dynamically orchestrated cellular elements in murine contact dermatitis that resembled lymphoid structures, which we termed inducible skin-associated lymphoid tissues (iSALT). We subsequently reported structures analogous to iSALT in human secondary syphilis, suggesting that iSALT can also exist in humans. Here, we studied ectopic lymphoid tissues in the lesions of LEP by immunohistochemistry and compared their characteristics with those of TLO. We demonstrated that LF of LEP were composed of B-cell follicles intermingled with CXCL13-expressing cells, distinct aggregations of T cells, and some blood vessels expressing peripheral node addressin. These findings indicate that LF of LEP can be considered as a type of iSALT.

GATA6-positive lung adenocarcinomas are associated with invasive mucinous adenocarcinoma morphology, hepatocyte nuclear factor 4α expression, and KRAS mutations

AIMS

GATA6 is known to play a role in lung development. However, its role in the carcinogenesis of lung cancer is not well studied. The aim of this study was to analyse GATA6 expression in lung adenocarcinomas (LAs) by immunohistochemistry (IHC) in order to define its association with clinicopathological characteristics.

METHODS AND RESULTS

IHC analysis of GATA6 was performed with tissue microarray slides containing 348 LAs. The association between GATA6 expression and clinicopathological parameters was evaluated. GATA6 expression in epithelial tumours other than lung cancer was also evaluated. GATA6 expression was found in 47 LAs (13.5%). This occurred more frequently in younger patients (P = 0.005), and was associated with the absence of lymph node metastasis (P =0.024), well-differentiated to moderately differentiated tumours (P < 0.001), the absence of lymphatic invasion (P = 0.020), and the absence of vascular invasion (P = 0.011). GATA6 expression was associated with mucin production (P < 0.001), the invasive mucinous adenocarcinoma subtype (P < 0.001), KRAS mutations (P = 0.026), expression of MUC2 (P < 0.001), CDX2 (P = 0.049), and MUC5AC (P < 0.001), and absence of expression of TTF-1 (P = 0.002). GATA6 expression was also associated with hepatocyte nuclear factor 4α (HNF4α) expression (P < 0.001). GATA6 expression tended to indicate better prognoses, whereas patients with HNF4α expression had significantly worse prognoses (P = 0.033). Of 270 tumours other than lung cancer, 110 expressed GATA6.

CONCLUSIONS

These findings suggest that GATA6 might interact with HNF4α and contribute to the development of mucinous-type LAs.

Effects of voltage strength during electroporation on the development and quality of in vitro-produced porcine embryos

This study was conducted to determine suitable conditions for an experimental method in which the CRISPR/Cas9 system is introduced into in vitro-produced porcine zygotes by electroporation. In the first experiment, when putative zygotes derived from in vitro fertilization (IVF) were electroporated by either unipolar or bipolar pulses, keeping the voltage, pulse duration and pulse number fixed at 30 V/mm, 1 msec and five repeats, respectively, the rate of blastocyst formation from zygotes electroporated by bipolar pulses decreased compared to zygotes electroporated by unipolar pulses. In the second experiment, the putative zygotes were electroporated by electroporation voltages ranging from 20 V/mm-40 V/mm with five 1-msec unipolar pulses. The rate of cleavage and blastocyst formation of zygotes electroporated at 40 V/mm was significantly lower (p < .05) than that of zygotes electroporated at less than 30 V/mm. Moreover, the apoptotic nuclei indices of blastocysts derived from zygotes electroporated by voltages greater than 30 V/mm significantly increased compared with those from zygotes electroporated by voltages less than 25 V/mm (p < .05). When zygotes were electroporated with Cas9 mRNA and single-guide RNA (sgRNA) targeting site in the FGF10 exon 3, the proportions of blastocysts with targeted genomic sequences were 7.7% (2/26) and 3.6% (1/28) in the embryos derived from zygotes electroporated at 25 V/mm and 30 V/mm, respectively. Our results indicate that electroporation at 25 V/mm may be an acceptable condition for introducing Cas9 mRNA and sgRNA into pig IVF zygotes under which the viability of the embryos is not significantly affected.

Possible Involvement of Human Mast Cells in the Establishment of Pregnancy via Killer Cell Ig-Like Receptor 2DL4

The involvement of mast cells in the establishment of pregnancy is unclear. Herein, we found that human mast cells are present in the decidual tissues of parous women and expressed a human-specific protein killer cell Ig-like receptor (KIR) 2DL4, a receptor for human leukocyte antigen G expressed on human trophoblasts. In contrast, decreased numbers of decidual mast cells and reduced KIR2DL4 expression were observed in these cells of infertile women who had undergone long-term corticosteroid treatment. Co-culture of the human mast cell line, LAD2, and human trophoblast cell line, HTR-8/SVneo, accelerated the migration and tube formation of HTR-8/SVneo cells in a KIR2DL4-dependent manner. These observations suggest the possible involvement of human mast cells in the establishment of pregnancy via KIR2DL4 and that long-term corticosteroid treatment may cause infertility by influencing the phenotypes of decidual mast cells.

Killer cell immunoglobulin-like receptor 2DL4 is expressed in and suppresses the cell growth of Langerhans cell histiocytosis

Killer cell immunoglobulin-like receptor (KIR) 2DL4 (CD158d) is a receptor for human leukocyte antigen-G. The function of KIR2DL4 has been reported in human natural killer cell lymphoma and mastocytosis, but not in Langerhans cell histiocytosis (LCH). Herein, we examined the expression and function of KIR2DL4 in LCHs. In pathological specimens, 27 of 36 LCH cases (75.0%) were immunohistochemically positive for KIR2DL4. Its expression was independent of age, gender, location, multi- or single-system, and the status of BRAFV600E immunostaining. We also confirmed the expression of KIR2DL4 mRNA and protein in the human LCH-like cell lines ELD-1 and PRU-1. KIR2DL4 protein was distributed in the membrane and cytoplasm of ELD-1 cells, but only in the cytoplasm of PRU-1 cells. An agonistic antibody against KIR2DL4 reduced phosphorylation of extracellular signal-regulated kinases (ERKs) and suppressed the cell growth of ELD-1 cells in a Src homology region 2 domain-containing phosphatase-2 dependent manner, but it had no effect in PRU-1 cells. These results suggest that KIR2DL4-mediated ERK suppression is a possible therapeutic target for LCH cells.