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Background: Although asbestos acts as a potent carcinogen in pleural mesothelial and pulmonary epithelial cells, it still remains unclear whether asbestos causes specific and characteristic gene alterations in these different kinds of target cells, because direct comparison in an identical patient is not feasible. We experienced a rare synchronous collision tumor composed of malignant pleural mesothelioma (MPM) and primary pulmonary adenocarcinoma (PAC) in a 77-year-old man with a history of long-term smoking and asbestos exposure, and compared the DNA copy number alteration (CNA) and somatic mutation in these two independent tumors. Methods: Formalin-fixed paraffin-embedded (FFPE) tissues of MPM and PAC lesions from the surgically resected specimen were used. Each of these MPM and PAC lesions exhibited a typical histology and immunophenotype. CNA analysis using SNP array was performed using the Illumina Human Omni Express-12_FFPE (Illumina, San Diego, CA, USA) with DNA extracts from each lesion. Somatic mutation analysis using next-generation sequencing was performed using the TruSeq Amplicon Cancer Panel (Illumina). Results: The CNA analysis demonstrated a marked difference in the frequency of gain and loss between MPM and PAC. In PAC, copy number (CN) gain was detected more frequently and widely than CN loss, whereas in MPM there was no such obvious difference. PAC did not harbor CNAs that have been identified in asbestos-associated lung cancer, but did harbor some of the CNAs associated with smoking. MPM exhibited CN loss at 9p21.2-3, which is the most common genetic alteration in mesothelioma. Conclusion: In this particular case, asbestos exposure may not have played a primary role in PAC carcinogenesis, but cigarette smoking may have contributed more to the occurrence of CN gains in PAC. This comparative genetic analysis of two different lesions with same amount of asbestos exposure and cigarette smoke exposure has provided information on differences in the cancer genome related to carcinogenesis.

Background: Vitreoretinal lymphoma (VRL) is a life- and sight-threatening disorder. The aim of this study was to analyze the usefulness of the cell block method for diagnosis of VRL. Methods: Sixteen eyes in 12 patients with VRL, and 4 eyes in 4 patients with idiopathic uveitis presenting with vitreous opacity were enrolled in this study. Both undiluted vitreous and diluted fluids were isolated during micro-incision vitrectomy. Cell block specimens were prepared in 19 eyes from diluted fluid containing shredding vitreous. These specimens were then submitted for HE staining as well as immunocytological analyses with antibodies against the B-cell marker CD20, the T-cell marker CD3, and cell proliferation marker Ki67. Conventional smear cytology was applied in 14 eyes with VRL using undiluted vitreous samples. The diagnosis of VRL was made based on the results of cytology, concentrations of interleukin (IL)-10 and IL-6 in undiluted vitreous, and immunoglobulin heavy chain gene rearrangement analysis. Results: Atypical lymphoid cells were identified in 14 out of 15 cell block specimens of VRL (positive rate: 93.3 %), but in 5 out of 14 eyes in conventional smear cytology (positive rate: 35.7 %). Atypical lymphoid cells showed immunoreactivity for CD20 and Ki67. Seven cell block specimens were smear cytology-negative and cell block-positive. The cell block method showed no atypical lymphoid cells in any patient with idiopathic uveitis. Conclusions: Cell block specimens using diluted vitreous fluid demonstrated a high diagnostic sensitivity and a low pseudo-positive rate for the cytological diagnosis of VRL. The cell block method contributed to clear differentiation between VRL and idiopathic uveitis with vitreous opacity., 背景：眼内リンパ腫（VRL）は視力・生命予後に影響を及ぼす疾患である。本研究ではVRLの診断における細胞塊（セルブロック）標本の有用性を検討することを目的とした。症例と方法：北海道大学病院眼科および他院を受診したVRL12例16眼、および硝子体混濁を呈した特発性ぶどう膜炎4例4眼を対象とした。小切開硝子体手術により、無希釈硝子体液および硝子体灌流液を採取した。19眼で、硝子体灌流液を用いたセルブロック標本を作製した。これらの標本を用いて特殊染色、およびB細胞マーカーである抗CD20抗体の免疫細胞化学的検討を行った。14眼では無希釈硝子体液を用いた塗抹細胞診を併せて行った。VRLの診断は、細胞診、無希釈硝子体液のIL-10, -6濃度、灌流液沈殿物から遺伝子再構成部位のモノクローナリティについて検討して行った。結果：VRLの15眼中14眼でセルブロック標本にて悪性リンパ腫細胞が検出された（陽性率：93.3％）。一方、塗抹細胞診では5眼で悪性細胞が検出された（陽性率：35.7％）。塗抹細胞診で陰性、セルブロックで陽性を示したIOL症例は7例8眼であった。特発性ぶどう膜炎では、悪性細胞が検出された症例はなかった（陽性率：0％）。VRL細胞はCD20陽性を示したが、特発性ぶどう膜炎ではCD20陽性細胞は検出されなかった。結語：硝子体灌流液を用いたセルブロック細胞診は、これまでの塗抹細胞診よりVRLの陽性率が高く、偽陽性も無かった。セルブロックは、VRLとぶどう膜炎との鑑別にも有用であることが示唆された。