天野 雄介

INTRODUCTION: The Hippo pathway consists of mammalian sterile 20-like kinase 1/2 (MST1/2), large tumor suppressor 1/2 (LATS1/2), and yes-associated protein (YAP)1. Herein, we present the first report on the significance of major Hippo pathway protein expression in oral squamous cell carcinoma (OSCC). METHODS: The analyses included oral epithelial dysplasia (OED, n = 7), carcinoma in situ (CIS, n = 14), and oral squamous cell carcinoma (OSCC, n = 109). RESULTS: Cytoplasmic expression of MST1, LATS1, and LATS2 was low in OED, CIS, and OSCC. The cytoplasmic expression of MST2 was high in OED (5/7 cases), CIS (9/14 cases), and poorly differentiated OSCC (8/8 cases) but was low/lost in a proportion of differentiated OSCC (60/101 cases). The expression of YAP1 was associated with differentiation; low YAP expression was significantly more frequent in well-differentiated OSCC (35/71 cases), compared to moderately and poorly differentiated OSCC (11/38 cases). An infiltrative invasion pattern was associated with a high expression of MST2 and high expression of YAP1. The high expression of YAP1 was associated with features of epithelial-to-mesenchymal transition (EMT), such as the loss of E-cadherin and high expression of vimentin, laminin 5, and Slug. High expression of protein arginine methyltransferase (PRMT) 1 or 5, which positively regulates YAP activity, was associated with the high expression of YAP1 (p < 0.0001). CONCLUSION: Among the major Hippo pathway proteins, MST2 displayed a distinctive expression pattern in a significant proportion of differentiated OSCC, suggesting a possible differential role for MST2 depending on the course of OSCC progression. A high YAP1 expression may indicate aggressive OSCC with EMT via PRMTs at the invasive front.

Background: Stromal patterns (SP), especially desmoplastic reactions, have recently gained attention as indicators of malignant potential in cancer. In this study, we explored the clinicopathological and prognostic significance of the SP in oral squamous cell carcinoma (OSCC). Materials and Methods: We reviewed 232 cases of surgically resected OSCC that were not treated with neoadjuvant chemoradiotherapy. We categorized the SP of the OSCC into four groups: immune/inflammatory (84 cases), mature (14 cases), intermediate (78 cases), or immature (56 cases). Results: The SP category was significantly associated with various clinicopathological factors, such as the histological grade, lymphovascular invasion, neural invasion, and a diffuse invasion pattern. For each of the factors, the immune/inflammatory type was associated with favorable categories, while the immature type was associated with unfavorable categories (p ≤ 0.001). The SP category was also shown to be a prognostic predictor: the 5-year relapse-free survival (RFS) rate was 72.0% for the immune/inflammatory type, 66.7% for the intermediate/mature type, and 31.2% for the immature type (p < 0.0001), and the 5-year overall survival (OS) rate was 85.1% for the immune/inflammatory type, 76.4% for the intermediate/mature type, and 50.0% for the immature type (p < 0.0001). In multivariate analyses, the SP category was identified as an independent prognostic factor for RFS and OS. Conclusion: Our SP categorization method provides valuable prognostic information in OSCC.

Methylthioadenosine phosphorylase (MTAP) is a rate-limiting enzyme in the methionine salvage pathway, which recycles one carbon unit that is lost during polyamine synthesis back into the methionine cycle. Although MTAP deficiency has been reported in various tumours, MTAP is overexpressed and might promote oncogenesis in other cancers, including prostate and colon cancer. Currently, little is known about the MTAP status of oral squamous cell carcinoma (OSCC). In this study, we immunohistochemically examined the expression of MTAP in surgically resected oral epithelial dysplasia (OED, n=7), carcinoma in situ (CIS) (n=16), and OSCC (n=118). In the normal epithelium, MTAP was only weakly expressed in the cytoplasm of the basal layer cells. In OED, CIS, and OSCC, MTAP was uniformly expressed in the cytoplasm of the dysplastic and cancer cells. In addition to cytoplasmic MTAP expression, 45 of 118 cases (38.1%) exhibited increased nuclear expression of MTAP in the cancer cells at the invasive front. Statistical analysis showed that the concomitant nuclear and cytoplasmic expression of MTAP was associated with a high budding score (p=0.0023); poor differentiation (p=0.0044); aggressive invasion patterns (p=0.0001); and features of epithelial-to-mesenchymal transition (EMT), such as loss of E-cadherin expression (p=0.0003) and upregulated expression of vimentin (p=0.0002), slug (p=0.0002), and laminin 5 (p<0.0001). High expression of protein arginine methyltransferase 1 or 5, the functions of which are reported to be inhibited in MTAP-deficient cancer, was associated with the concomitant nuclear and cytoplasmic expression of MTAP (p<0.0001). Concomitant nuclear and cytoplasmic expression of MTAP was marginally significantly associated with worse 5-year relapse-free survival (p=0.045). These findings suggest that MTAP not only plays a role in the oncogenesis of OSCC, but that it might also make it more aggressive by inducing EMT through its activity in the methionine salvage pathway.

RATIONALE: Salivary duct carcinoma (SDC) is a rare and highly aggressive cancer with a poor prognosis. SDC demonstrates a potential for invasive growth with early regional and distant metastasis to organs, such as bone, lung, liver, and brain. Because, adrenal gland metastasis from SDC is rare, its treatment options are not well established. Herein, we report a case of SDC metastasis from the parotid gland to the adrenal gland, which was successfully treated by surgery. PATIENT CONCERNS: The patient had an abnormal but painless lump on the right parotid gland. The size of the mass had increased over a period of 3 years. The patient underwent complete removal of the right parotid gland and radical neck dissection followed by adjuvant radiotherapy and chemotherapy. Two years later, a mass was identified in the left adrenal gland by computed tomography. As no local recurrence or metastasis to other organs was observed, the patient underwent adrenalectomy. DIAGNOSES: Metastasis of SDC in the adrenal gland was confirmed by histopathological examination of the adrenalectomized specimen. INTERVENTIONS: After adrenalectomy, the patient was followed-up without adjuvant therapy. OUTCOMES: The patient was well and alive during the 13-month postoperative follow-up period without any complications. LESSONS: Surgical resection of solitary metastatic lesion may show a survival benefit with metastatic SDC.

INTRODUCTION: Breast adenomyoepithelioma (AME) is a rare tumor composed of myoepithelial cells and ductal or luminal cells. Most cases of AME are benign, but rare cases in which either or both cell types exhibited malignant features have been reported. Due to its rarity, no diagnostic criteria for malignancy have been established for AME. PATIENT CONCERNS: A 64-year-old woman presented with a mass in her right breast. Fine-needle aspiration cytology and biopsy examinations revealed lesions composed of spindle-shaped cells and round epithelial cells. AME was suspected, and partial mastectomy was performed. DIAGNOSIS: The tumor specimen showed AME, which mainly consisted of spindle-shaped myoepithelial cells with slight atypia, admixed with tubular luminal cells and small areas of atypical intraductal proliferative lesions. No apparent features of malignancy, such as necrosis or invasion, were seen in the myoepithelial cells or the luminal or intraductal component. However, the atypical intraductal component exhibited focal nuclear atypia, a cribriform pattern, and moderate to strong membranous human epidermal growth factor receptor 2 (HER2) immunoreactivity. HER2 amplification was detected in focal regions of the atypical intraductal component by fluorescence in situ hybridization (FISH), which resulted in a diagnosis of AME with ductal carcinoma in situ. OUTCOMES: The patient did not receive further therapy and was free from tumor recurrence at 23 months after the operation. CONCLUSION: HER2 FISH might be useful for evaluating suspected AME tumors for malignancy when an atypical ductal lesion that lacks definitive features of malignancy is encountered.

口腔領域の細胞診は、ブラシや綿棒などで粘膜を擦過して細胞を採取するので、侵襲性が少なく、繰り返し実施可能である。そのため、口腔癌検診や初診時のスクリーニング目的に実施されることが多い。口腔粘膜疾患細胞診の判定区分について解説し、口腔潜在的悪性疾患(紅板症、白板症、口腔扁平苔癬)、口腔上皮性異形成、扁平上皮癌(上皮内癌含む)における病理学的および細胞学的な項目を中心に概説した。

今回、我々は頭皮皮膚原発と考えられた血管肉腫の胸水浸潤例を経験した。症例は70歳代の男性で、頭部腫瘤を切除され血管肉腫と診断された。術後6ヵ月後に胸水細胞診が施行され腫瘍細胞は、大小の集塊や、印環様細胞、細胞質内小腺腔構造、細胞相互封入像(Pair cell)、および複数細胞からなる細胞封入像(渦巻き様構造)として認められた。免疫組織化学的にCD31、D2-40、Vimentinに陽性であった。上記所見と臨床所見より血管肉腫の胸水浸潤と診断した。(著者抄録)

小児の縦隔に発生したHistiocytic sarcomaの1例を経験したので報告する。患者は4歳男児、感冒様症状が出現したため近医を受診したところ、画像上縦隔の拡大が指摘された。診断目的で臨床的に転移巣と考えられた頭部皮膚の生検が施行された。組織学的には、真皮から皮下組織にかけて結節性病変が認められ、中等大の類円形細胞の増殖から構成されていた。免疫染色ではCD45LCA、CD68、CD163陽性、CD1a、CD3、CD20、CD79a、CD246、MPO、lysozyme陰性であり、HE像と併せ、Histiocytic sarcomaと診断した。(著者抄録)

Herein, we present a case report of the metastasis of a clear cell renal cell carcinoma (ccRCC) with an eosinophilic cell component to the skin of the submandibular region. An eosinophilic component has not been reported previously in the histological findings of ccRCC. The patient was a 74yearold man who had a painless papula in the right submandibular region. Six years earlier, he had undergone nephrectomy and had been diagnosed with stage 1 ccRCC (pT1a, N0, M0). At the current presentation, the dermis in the resected specimen was composed of a clear cell neoplasm with glycogen deposits. Upon immunohistochemical analysis, the clear cells were found to be positive for CD10 and vimentin. As these findings were similar to those from the nephrectomy specimen, the cutaneous lesion on the skin of the submandibular region was confirmed to be a lesion of the metastatic ccRCC. Even when a lowstage ccRCC with an eosinophilic cell component is diagnosed, critical pathological and clinical examinations are needed because distant metastases may occur to the head and neck region, as in this case. Furthermore, when a skin tumor is found in the head and neck region, metastatic RCC must be considered in the differential diagnosis.

50代後半女性の顎下部に、径約15cmの腫瘤を認め、切除された。病理組織では紡錘形細胞が粘液腫様基質を伴い増生し、一部に扁平上皮化生を認める多形腺腫がみられ、これと移行するように異型の高度な紡錘形細胞が密に増殖する肉腫様の病変がみられ、破骨型巨細胞の出現も目立った。免疫染色では、肉腫様の腫瘍細胞は筋上皮の形質を示し、多形腺腫由来筋上皮癌と診断した。高い増殖能と被膜浸潤を伴い、術後早期に局所再発と肺転移巣の増大により死亡した。多形腺腫由来筋上皮癌は悪性度が高く、正確に診断する必要があると考えられた。(著者抄録)

The active form of vitamin D(3), 1alpha,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)], is a potent ligand for the nuclear receptor vitamin D receptor (VDR) and induces myeloid leukemia cell differentiation. The cardiotonic steroid bufalin enhances vitamin D-induced differentiation of leukemia cells and VDR transactivation activity. In this study, we examined the combined effects of 1,25(OH)(2)D(3) and bufalin on differentiation and VDR target gene expression in human leukemia cells. Bufalin in combination with 1,25(OH)(2)D(3) enhanced the expression of VDR target genes, such as CYP24A1 and cathelicidin antimicrobial peptide, and effectively induced differentiation phenotypes. An inhibitor of the Erk mitogen-activated protein (MAP) kinase pathway partially inhibited bufalin induction of VDR target gene expression. 1,25(OH)(2)D(3) treatment induced transient nuclear expression of VDR in HL60 cells. Interestingly, bufalin enhanced 1,25(OH)(2)D(3)-induced nuclear VDR expression. The MAP kinase pathway inhibitor increased nuclear VDR expression induced by 1,25(OH)(2)D(3) and did not change that by 1,25(OH)(2)D(3) plus bufalin. A proteasome inhibitor also enhanced 1,25(OH)(2)D(3)-induced CYP24A1 expression and nuclear VDR expression. Bufalin-induced nuclear VDR expression was associated with histone acetylation and VDR recruitment to the CYP24A1 promoter in HL60 cells. Thus, the Na(+),K(+)-ATPase inhibitor bufalin modulates VDR function through several mechanisms, including Erk MAP kinase activation and increased nuclear VDR expression.

1,25-Dihydroxyvitamin D(3) [1,25(OH)(2)D(3); 1,25-dihydroxycholecalciferol or calcitriol] is the active form of vitamin D(3), a lipid-soluble vitamin that plays a role in calcium and bone metabolism. Recently, vitamin D(3) has been shown to function in cancer prevention, immunity and cardiovascular regulation. 1,25(OH)(2)D(3) exhibits physiological and pharmacological effects by activating the vitamin D receptor (VDR), a transcription factor of the nuclear receptor superfamily. 1,25(OH)(2)D(3) plays a role in maintaining oral health through its effects on bone and mineral metabolism and innate immunity, and several VDR gene polymorphisms have been reported to be associated with periodontal disease. VDR ligands should prove to be useful in the treatment and prevention of periodontal disease.