Tatsuya Takenouchi

The prevalence of Merkel cell polyomavirus in Japanese patients with Merkel cell carcinoma

BACKGROUND A novel polyomavirus, the Merkel cell polyomavirus (MCPyV) has been implicated in the pathogenesis of Merkel cell carcinoma (MCC); however, the prevalence of MCPyV in Japan has not been extensively investigated. OBJECTIVE To clarify the prevalence of MCPyV in Japanese patients with MCC. METHODS MCPyV DNA was examined by polymerase chain reaction (PCR) in formalin-fixed paraffin-embedded (FFPE) or frozen tissue samples from 26 patients with MCC diagnosed in four medical centers in Japan. Immunohistochemistry was simultaneously performed using a monoclonal antibody against the viral large T (LT) antigen. FFPE samples from basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) were also analyzed as controls. RESULTS Twenty-three out of 26 cases (88.5%) were positive for MCPyV DNA by PCR. The amplified products harbored 4 patterns of mutations. Phylogenetic analysis demonstrated that one of our strains was closely related to the other Japanese strains previously reported. The LT antigen was expressed in various degrees in 20 of 26 cases (76.9%) by immunohistochemistry. Histological type had little relation to CM2B4 positivity, whereas 3 of 5 trabecular-type tumors showed no staining. The immunoreactivity for CM2B4 did not correlate with the relative viral DNA load. In BCC and SCC, the LT antigen was immunohistochemically positive, but MCPyV DNA was not detected by PCR. The cells around some MCC and non-MCC tumors were stained with CM2B4 with a distribution similar to CD20- and CD45RO- (especially CD8-) positive lymphocytes. CONCLUSION MCPyV was highly positive in Japanese patients with MCC. It is of note that the positive rate differs depending upon the detection method.

Expression of cutaneous fatty acid-binding protein and its mRNA in rat skin.

Cutaneous fatty acid-binding protein (C-FABP) has been purified from rat skin. Since there was little information about the role of C-FABP in the skin, we investigated the expression of C-FABP and its mRNA in normal rat skin using an immunohistochemical technique and in situ hybridization. In the epidermis, C-FABP mRNA was found to be expressed in basal cells and highly in prickle cells, while C-FABP itself was strongly expressed in the upper prickle and the granullar cell layers. In sebaceous glands, both C-FABP and its mRNA were expressed in both peripheral and differentiating cells, although the expression of C-FABP mRNA gradually reduced during differentiation of sebocytes. Since epidermis and sebaceous glands are active sites of fatty acid synthesis, these results suggest that C-FABP may have important roles in the transport and synthesis of fatty acids.

Cutaneous ciliated cyst: a case report and histochemical, immunohistochemical, and ultrastructural study

A 19‐year‐old woman with a cutaneous ciliated cyst on her buttock is reported. Histological, histochemical, and electron microscopic studies revealed ciliated cells, mucinous cells showing merocrine secretion, and areas of squamous metaplasia in the cyst wall. This is the first case of cutaneous ciliated cyst that contained non‐ciliated mucinous cells as a component.

Establishment and characterization of a clear-cell sarcoma (malignant melanoma of soft parts) cell line.

A clear cell sarcoma (CCS) cell line, designated as NCS-1, was established in monolayer culture from a xenograft line originating from a metastatic CCS. Marked karyotypic aberrations and tumorigenicity in nude mice revealed the malignant derivation of the NCS-1 cell line. These cells contained abundant glycogen and were amelanotic by light microscopy. By electron microscopy, however, melanosomes in various developmental stages were seen, and some of them were partially melanized. The electron microscopic dopa reaction revealed the presence of tyrosinase activity. Enzyme-linked immunoadsorbent assay revealed that NCS-1 cells expressed a 75-kDa glycoprotein which was identified as a marker of highly differentiated melanoma cells. From these results, NCS-1 cells were found to retain both cytochemical and morphological properties of CCS. Application of NCS-1 cells to a panel of monoclonal antibodies recognizing melanocytic differentiation antigens showed that they corresponded approximately to highly differentiated melanoma cells. In conclusion, the present study strongly supports the close relationship between CCS and malignant melanoma.

A case of localized follicular hamartoma: an ultrastructural and immunohistochemical study

We report the case of a 22‐year‐old woman with a nevoid plaque that we termed localized follicular hamartoma. The plaque was noticed at puberty on a unilateral site of the face and scalp. Clinically, it revealed numerous, skin‐colored to light brown papules alone and in groups, occasionally bearing a single hair. Histologically, branched epithelial nests of squamoid and/or basaloid cells were revealed in connection with the interfollicular epidermis and the upper portions of hair follicles, of which the lower portions showed normal structures. Immunohistochemically, the epithelial nests showed the keratin expression consisted with that of the infundibular epithelium. S‐100‐positive cells were found in the epithelial nests and the stroma. Factor XIIIa‐positive dendritic cells were numerous in adjacent to the epithelial nests. Ultrastructurally, immature melanocytes with a small number of premelanosomes and Merkel cells were found in the nests. Stromal dendritic cells showed the adherent features of the cytoplasmic processes to anchoring fibrils or basal lamina of the epithelial nests. From these findings, our case is a hamartoma, which seems to be an abortive growth of secondary hair germs with a limited differentiation to the upper follicular portion.

Angiolymphoid hyperplasia with eosinophilia presenting multinucleated cells in histology: an ultrastructural study

A case of angiolymphoid hyperplasia with eosinophilia arising on the face of a woman is reported. Histologically, the uniqueness of this case is the presence of multinucleated cells (MNCs), besides the conventional dermal changes. Electron microscopy showed that some of the apparent MNCs are clusters of endothelial cells forming immature vascular lumens with numerous microvilli, and the other MNCs displayed the recognized features of fibrohistiocytic or myofibroblastic cells. Immunohistochemically, some MNCs were positive for Ulex europaeus agglutinin and Factor VIII‐related antigen. From these findings, some of the MNCs are histologically endothelial sprouts, and the others are fibrohistiocytic cells in the present case.

Peripheral blood Th9 cells are a possible pharmacodynamic biomarker of nivolumab treatment efficacy in metastatic melanoma patients

ABSTRACT Although nivolumab is associated with a significant improvement in overall survival and progression-free survival, only 20 to 40% of patients experience long-term benefit. It is therefore of great interest to identify a predictive marker of clinical benefit for nivolumab. To address this issue, the frequencies of CD4+ T cell subsets (Treg, Th1, Th2, Th9, Th17 and Th22), CD8+ T cells, and serum cytokine levels (IFNγ, IL-4, IL-9, IL-10, TGF-β) were assessed in 46 patients with melanoma. Eighteen patients responded to nivolumab, and the other 28 patients did not. An early increase in Th9 cell counts during the treatment with nivolumab was associated with an improved clinical response. Before the first nivolumab infusion, the responders displayed elevated serum concentrations of TGF-β compared to non-responders. Th9 induction by IL-4 and TGF-β was enhanced by PD-1/PD-L1 blockade in vitro. The role of IL-9 in disease progression was further assessed using a murine melanoma model. In vivo IL-9 blockade promoted melanoma progression in mice using an autochthonous mouse melanoma model, and the cytotoxic ability of murine melanoma-specific CD8+ T cells was enhanced in the presence of IL-9 in vitro. These findings suggest that Th9 cells, which produce IL-9, play an important role in the successful treatment of melanoma patients with nivolumab. Th9 cells therefore represent a valid biomarker to be further developed in the setting of anti-PD-1 therapy.

Risk factors for lymph node metastasis in squamous cell carcinoma of the skin

背景: 有棘細胞癌 (SCC) の治療において所属リンパ節の取り扱いが予後に与える影響は大きい。センチネルリンパ節生検はSCCにも適用されるが全例に行うのは現実的ではなく, ハイリスク症例の選別が必要となる。目的: SCCにおけるリンパ節転移のリスク因子の同定対象・方法: SCC118例を対象とし, 初回治療時もしくは経過中のリンパ節転移の有無を目的変数とした多重ロジスティックモデルを構築。説明変数として年齢, 性別, 発生部位, 腫瘍径, tumor thickness, level分類, 浸潤様式 (胃癌取り扱い規約に準ずる) の計7因子を共変量とした。結果: リンパ節転移の有意な相対リスクを示したのは, 手・足原発 (頭頸部に対するオッズ比8.3) と浸潤様式INFγ (α・βに対するオッズ比5.9) の2因子であった。結論: 手・足原発もしくは浸潤様式INFγを示すSCCは, リンパ節転移のハイリスク症例として取り扱うべきである。

Popliteal lymph node metastasis from malignant melanoma

Sentinel lymph node (SLN) biopsy has become widely accepted as a method of staging in the regional lymph nodes of patients with malignant melanoma. Popliteal lymph nodes have been rarely identified as SLNs in patients with melanoma at or distal to the knee. However, its significance has not been well established. We reported a case of a patient with melanoma on the heel, who had positive SLN metastases in both popliteal and groin lymph nodes. In addition, experience with the past cases metastasized to popliteal lymph nodes in our hospitals were reviewed. Among 76 patients with melanoma of the distal lower limb, five (6.6%) developed popliteal lymph node metastases in its clinical course. The primary tumor sites in four of five patients were located on the heel, especially on the lateral or proximal aspects. Although elective lymphadenectomy of popliteal node seems to be unnecessary considering the low incidence of metastasis, once the popliteal node is identified as SLN on lymphoscintigraphy, biopsy procedureshould be performed. [Skin Cancer (Japan) 2003; 18: 298-302]

Metastatic sweat gland carcinoma successfully treated with thermoradiation therapy.

A 73-year-old female presented with a small ulcerated nodule on her left heel. It was excised with a margin of 10mm and reconstructed by skin grafting. The histological diagnosis was sweat gland carcinoma. Four months after the operation, a rapidly growing subcutaneous tumor was recognized on her left leg. The biopsy specimen showed metastatic sweat gland carcinoma. A combination therapy of intravenous cisplatin, 5-fluorouracil and subcutaneous peplomycin with 30Gy of irradiation was tried, but the patient could not endure its severe side effects. Subsequently, she was treated with 30.5Gy of additional irradiation combined with hyperthermia. A great response was observed. Wide local excision and left groin dissection followed. There was no evidence of metastasis during 5 years after the therapy. [Skin Cancer (Japan) 2002; 17: 123-126]