Published papers

Background: Japan’s health insurance covers multigene panel testing. This study aimed to determine the potential availability and utility of gene panel testing clinically in gynecologic oncology. Methods: We analyzed the characteristics of patients with gynecologic cancer who underwent gene panel testing using FoundationOne® CDx or OncoGuide™ NCC Oncopanel between November 2019 and October 2022. Results: Out of 102 patients analyzed, 32, 18, 43, 8, and 1 had cervical, endometrial, ovarian cancers, sarcoma, and vaginal cancer, respectively. Druggable gene alteration was found in 70 patients (68.6%; 21 with cervical cancer, 15 with endometrial cancer, 28 with ovarian cancer, 5 with sarcoma, and 1 with other). The most common druggable gene alteration was PIK3CA mutation (n = 21), followed by PTEN mutation (n = 12) and high tumor mutation burden (TMB-H) (n = 11). TMB-H was detected in 5 patients with cervical cancer, 5 with endometrial cancer, and 1 with endometrial stromal sarcoma. Eleven patients (10.8%) received molecularly targeted therapy according to their gene aberrations. Gene panel testing was mostly performed when the second-line treatment was ineffective. Of all 102 patients, 60 did not have recommended treatment, and 15 died or had worsened conditions before obtaining the test results. Conclusion: Through multigene panel testing, although many patients had druggable gene alterations, 10.8% of them received the recommended treatment. TMB-H was mainly observed in cervical/endometrial cancer, suggesting its potential as a therapeutic biomarker of immune checkpoint inhibitors. Furthermore, patients’ prognosis and performance status should be considered before performing the test.

The first prophylactic vaccine against human papillomavirus (HPV) 16 and HPV18 was licensed in Japan in 2009. HPV vaccine effectiveness against high-grade cervical lesions has been demonstrated among young Japanese women, but evidence of its effects on invasive cervical cancer (ICC) is lacking. Using data from two different cancer registries, we compared recent trends of new ICC cases by age group using Poisson regression analysis. We also analyzed time trends in HPV16/18 prevalence among 1414 Japanese women aged <40 years newly diagnosed with ICC in the past decade. Based on the population-based cancer registry, the incidence of ICC among young women aged 20–29 years showed a significant decline from 3.6 to 2.8 per 100 000 women-years during 2016–2019, but no similar decline was observed for older age groups (p < 0.01). Similarly, using data from the gynecological cancer registry of the Japan Society of Obstetrics and Gynecology, the annual number of ICCs among women aged 20–29 years also decreased from 256 cases to 135 cases during 2011–2020 (p < 0.0001). Furthermore, a declining trend in HPV16/18 prevalence in ICC was observed only among women aged 20–29 years during 2017–2022 (90.5%–64.7%, p = 0.05; Cochran–Armitage trend test). This is the first report to suggest population-level effects of HPV vaccination on ICC in Japan. Although the declining trend in HPV16/18 prevalence among young women with ICC supports a causal linkage between vaccination and results from cancer registries, further studies are warranted to confirm that our findings are attributable to vaccination.

Background Understanding the mechanisms of non-T cell inflamed tumor microenvironment (TME) and their modulation are important to improve cancer immunotherapies such as immune checkpoint inhibitors. The involvement of various immunometabolisms has recently been indicated in the formation of immunosuppressive TME. In this study, we investigated the immunological roles of stearoyl-CoA desaturase 1 (SCD1), which is essential for fatty acid metabolism, in the cancer immune response. Methods We investigated the roles of SCD1 by inhibition with the chemical inhibitor or genetic manipulation in antitumor T cell responses and the therapeutic effect of anti-programmed cell death protein 1 (anti-PD-1) antibody using various mouse tumor models, and their cellular and molecular mechanisms. The roles of SCD1 in human cancers were also investigated by gene expression analyses of colon cancer tissues and by evaluating the related free fatty acids in sera obtained from patients with non-small cell lung cancer who were treated with anti-PD-1 antibody. Results Systemic administration of a SCD1 inhibitor in mouse tumor models enhanced production of CCL4 by cancer cells through reduction of Wnt/β-catenin signaling and by CD8 + effector T cells through reduction of endoplasmic reticulum stress. It in turn promoted recruitment of dendritic cells (DCs) into the tumors and enhanced the subsequent induction and tumor accumulation of antitumor CD8 + T cells. SCD1 inhibitor was also found to directly stimulate DCs and CD8 + T cells. Administration of SCD1 inhibitor or SCD1 knockout in mice synergized with an anti-PD-1 antibody for its antitumor effects in mouse tumor models. High SCD1 expression was observed in one of the non-T cell-inflamed subtypes in human colon cancer, and serum SCD1 related fatty acids were correlated with response rates and prognosis of patients with non-small lung cancer following anti-PD-1 antibody treatment. Conclusions SCD1 expressed in cancer cells and immune cells causes immunoresistant conditions, and its inhibition augments antitumor T cells and therapeutic effects of anti-PD-1 antibody. Therefore, SCD1 is an attractive target for the development of new diagnostic and therapeutic strategies to improve current cancer immunotherapies including immune checkpoint inhibitors.

Human papillomavirus type 31 (HPV31) is detected less frequently in cervical cancer than two major causative types, HPV16 and HPV18. Here, we report a comprehensive analysis of HPV31 genome sequences in cervical lesions collected from Japanese women. Of 52 HPV31-positive cervical specimens analyzed by deep sequencing, 43 samples yielded complete genome sequences of around 7900 base pairs and 9 samples yielded partially deleted genome sequences. Phylogenetic analysis showed that HPV31 variant distribution was lineage A in 19 samples (36.5%), lineage B in 28 samples (53.8%), and lineage C in 5 samples (9.6%), indicating that lineage B variants are dominant among HPV31 infections in Japan. Deletions in the viral genome were found in the region from the E1 to L1 genes, but all the deleted genomes retained the E6/E7 genes. Among intra-patient nucleotide variations relative to a consensus genome sequence in each sample, C-to-T substitutions were most frequently detected, followed by T-to-C and C-to-A substitutions. High-frequency, intra-patient mutations (>10%) in cervical cancer samples were found in the E1, E2, and E7 genes, and all of them were nonsynonymous substitutions. The enrichment of high-frequency nonsynonymous substitutions strongly suggests that these intra-patient mutations are positively selected during the development of cervical cancer/precancer.

We previously reported that the inhibition of stearoyl-CoA desaturase 1 (SCD1) enhances the antitumor function of CD8+ T cells indirectly via restoring production of DC recruiting chemokines by cancer cells and subsequent induction of antitumor CD8+ T cells. In this study, we investigated the molecular mechanism of direct enhancing effects of SCD1 inhibitors on CD8+ T cells. In vitro treatment of CD8+ T cells with SCD1 inhibitors enhanced IFN-γ production and cytotoxic activity of T cells along with decreased oleic acid and esterified cholesterol, which is generated by cholesterol esterase, acetyl-CoA acetyltransferase 1 (ACAT1), in CD8+ T cells. The addition of oleic acid or cholesteryl oleate reversed the enhanced functions of CD8+ T cells treated with SCD1 inhibitors. Systemic administration of SCD1 inhibitor to MCA205 tumor-bearing mice enhanced IFN-γ production of tumor-infiltrating CD8+ T cells, in which oleic acid and esterified cholesterol, but not cholesterol, were decreased. These results indicated that SCD1 suppressed effector functions of CD8+ T cells through the increased esterified cholesterol in an ACAT1-dependent manner, and SCD1 inhibition enhanced T cell activity directly through decreased esterified cholesterol. Finally, SCD1 inhibitors or ACAT1 inhibitors synergistically enhanced the antitumor effects of anti-PD-1 antibody therapy or CAR-T cell therapy in mouse tumor models. Therefore, the SCD1–ACAT1 axis is regulating effector functions of CD8+ T cells, and SCD1 inhibitors, and ACAT1 inhibitors are attractive drugs for cancer immunotherapy.

Metastatic pancreatic cancer is a rare condition and cases of pancreatic metastasis from cervical cancer are infrequently reported. Furthermore, the incidence rates of pancreatic tumors as the cause of pancreatitis and of pancreatitis in patients with pancreatic tumors are similarly low. Pancreatitis may occur when a tumor obstructs the pancreatic duct. This condition may be difficult to manage and significantly reduces the quality of life because of severe abdominal pain. Here, we present a rare case of obstructive pancreatitis caused by pancreatic metastasis from cervical squamous-cell carcinoma, pathologically confirmed using endoscopic ultrasonography-guided fine-needle biopsy and treated with palliative irradiation to achieve rapid therapeutic relief. It is important to obtain appropriate tissue samples, confirm the pathological diagnosis, and compare the pathological findings with those of the primary tumor to select the appropriate treatment for obstructive pancreatitis caused by a metastatic pancreatic tumor.

抗PD-1/PD-L1阻害薬は、治療前に腫瘍抗原特異的なCD8陽性T細胞が腫瘍組織に浸潤している腫瘍(hot tumor)では、がん細胞などが発現するPD-L1によるエフェクターCD8陽性T細胞抑制の解除により、がん細胞を排除できる。しかし、多くの症例ではCD8陽性T細胞浸潤が少なく(cold tumor)、抗PD-1/PD-L1阻害薬単独投与の効果は限定的であり、この治療抵抗性機序を解明して治療効果を増強する方法の開発が期待されている。我々は、様々なヒトがんの網羅的遺伝子発現解析により、cold tumorの中には、脂肪酸不飽和化酵素であるStearoyl-CoA desaturase 1(SCD1)の高発現をはじめとする、脂質代謝異常が深く関与するサブタイプが存在することを見出した。そこで、本研究では、脂肪酸代謝の抗腫瘍免疫応答への関与及び、それを標的としたがん免疫療法の可能性を検討した。まず、各種マウスがん細胞株を移植したマウス腫瘍モデルを用いて、SCD1阻害剤投与により、抗腫瘍免疫応答を増強できるかを検討した。その結果、SCD1阻害剤投与群において、腫瘍内樹状細胞(DC)のCD80/CD86やCD83の発現上昇、およびその浸潤増加が認められた。更に、CD8陽性T細胞の腫瘍内浸潤数の増加も観察され、所属リンパ節及び腫瘍組織内で、腫瘍抗原特異的T細胞の誘導が増強された。腫瘍内浸潤CD8陽性T細胞におけるPD-1などの共刺激分子の発現もSCD1阻害剤投与群において増強されていたので、SCD1阻害剤と抗PD-1抗体の併用療法の効果を評価した。その結果、抗PD-1抗体単独投与ではほとんど効果を示さないがん細胞株においても、両薬の併用によって相乗的な抗腫瘍効果が観察され、完全奏効例も認められた。SCD1阻害剤のin vitroでの免疫細胞に対する効果を評価したところ、DC及びCD8陽性T細胞に直接作用し、その機能を増強することも明らかとなった。以上より、がん微小環境における脂質代謝の制御により、cold tumorをhot tumorに変え、免疫チェックポイント阻害薬の治療効果を向上させる可能性が示された。(著者抄録)

子宮頸部上皮内病変(CIN)へのレーザー蒸散術は、切除検体の病理診断が行われないため症例ごとに手術適応を十分に検討し術後の経過観察を慎重に行う必要がある。今回当科でCIN2もしくはCIN3と診断され蒸散術を行った1469例のうち、術後に子宮頸がんを認めた症例について検討を行った。蒸散術後の経過観察中に子宮頸がんと診断された症例は1469例中18例(1.2%)で、臨床進行期分類(FIGO 2008)はIA1期8例、IB1期10例であった。子宮頸がん診断までの中央値は11ヵ月(3～72.6ヵ月)で、15例(83%)は術後18ヵ月以内に診断されていた。治療はIA1期の6例は円錐切除術のみ、2例で円錐切除術後に拡大単純子宮全摘出術、IB1期の10例は広汎子宮全摘出術を行った。いずれも再発を認めていない。CINに対する蒸散術後は浸潤がんが発生する可能性を念頭におき慎重に経過観察する必要がある。(著者抄録)

子宮頸部胃型粘液性癌はハイリスクHPV感染との関連が低く稀な組織型であり,予後不良な疾患とされる.本研究では当科で経験した子宮頸部胃型粘液性癌について検討を行った.対象症例は12例であり,年齢の中央値は50歳(range:33～60歳),観察期間の中央値は16ヵ月(range:3～29ヵ月),臨床進行期(FIGO 2008)はIB1期6例,IB2期4例,IIB期1例,IVA期1例であった.初回治療として,手術を行った症例は12例中9例,同時化学放射線療法(concurrent chemoradiation therapy:CCRT)を行った症例は3例であった.手術を行った9症例のうち5例(56%)は術前の細胞診および組織診において浸潤癌の所見を認めなかった.12例中5例(42%)に再発を認め,うち4例は治療終了後12ヵ月以内に再発し,いずれも腹膜播種によるものであった.子宮頸部胃型粘液性癌は予後不良な組織型であり,治療後早期に再発する可能性を念頭に置き,慎重な経過観察を行う必要がある.(著者抄録)

進行子宮頸癌は極めて難治性で，有効な新規治療法の開発が望まれている．腫瘍浸潤リンパ球輸注療法（TIL療法）は米国国立衛生研究所（NIH）で開発された養子免疫療法で，進行子宮頸癌において約20％の完全奏効（CR）が報告されている．注目すべき特徴はCRとなった症例では，その後の再発が低率で，治癒が期待できるとされていることである．また，免疫チェックポイント阻害薬の無効例であっても高い効果が報告されている．TIL療法の手順では，まず最初に患者自身の腫瘍を切除して浸潤リンパ球を抽出し，培養28日目に活性を有するリンパ球を選択する．このリンパ球をフィーダー細胞である健常人由来の末梢血単核球と共培養して14日で約1,000倍に増殖させ（急速拡大培養），骨髄抑制処置を行った患者に輸注する．輸注後は抗腫瘍効果を増強するためIL-2を8時間ごと5回投与する．我々は，2021年10月より先進医療の枠組みのもと，第3種再生医療として進行子宮頸癌症例を対象としたTIL療法の第2相臨床試験を実施している（jRCTc031200283）．先進医療と並行して前臨床試験を実施し，医師主導治験への導出を目指す．

Persistent infections with two types of human papillomaviruses (HPV), HPV16 and HPV18, are the most common cause of cervical cancer (CC). Two viral early genes, E6 and E7, are associated with tumor development, and expressions of E6 and E7 are primarily regulated by a single viral promoter: P97 in HPV16 and P105 in HPV18. We previously demonstrated that the homeobox D9 (HOXD9) transcription factor is responsible for the malignancy of HPV16-positive CC cell lines via binding to the P97 promoter. Here, we investigated whether HOXD9 is also involved in the regulation of the P105 promoter using two HPV18-positive CC cell lines, SKG-I and HeLa. Following the HOXD9 knockdown, cell viability was significantly reduced, and E6 expression was suppressed and was accompanied by increased protein levels of P53, while mRNA levels of TP53 did not change. E7 expression was also downregulated and, while mRNA levels of RB1 and E2F were unchanged, mRNA levels of E2F-target genes, MCM2 and PCNA, were decreased, which indicates that the HOXD9 knockdown downregulates E7 expression, thus leading to an inactivation of E2F and the cell-cycle arrest. Chromatin immunoprecipitation and promoter reporter assays confirmed that HOXD9 is directly associated with the P105 promoter. Collectively, our results reveal that HOXD9 drives the HPV18 early promoter activity to promote proliferation and immortalization of the CC cells.

Background: Human papillomavirus (HPV) type 67 is phylogenetically classified into Alphapapillomavirus species 9 (alpha-9) together with other carcinogenic types (HPV16, 31, 33, 35, 52 and 58), but is the only alpha-9 type defined as possibly carcinogenic. This study aimed to determine whole-genome sequences of HPV67 isolated from Japanese women with cervical cancer or cervical intraepithelial neoplasia (CIN) to better understand the genetic basis of the oncogenic potential of HPV67. Methods: Total cellular DNA isolated from cervical exfoliated cells that were single positive for HPV67 (invasive cervical cancer, n = 2; CIN3, n = 6; CIN 2, n = 1; CIN1, n = 2; the normal cervix, n = 1) was subjected to PCR to amplify HPV67 DNA, followed by next generation sequencing to determine the complete viral genome sequences. Variant lineages/sublineages were assigned through viral whole-genome phylogenetic analysis. The transcriptional activity of the virus early promoter was assessed by luciferase reporter assays in cervical cancer cell lines. Results: Phylogenetic analyses of HPV67 genomes from Japan (n = 12) revealed that 11 belonged to lineage A (sublineage A1, n = 9; sublineage A2, n = 2) and one belonged to lineage B. All cancer cases contained sublineage A1 variants, and one of these contained an in-frame deletion in the E2 gene. The long control region of the HPV67 genome did not induce transcription from the virus early promoter in HeLa cells, but showed weak transcriptional activity in CaSki cells. Conclusions: The single detection of HPV67 in cervical cancer and precancer specimens strongly suggests the carcinogenic potential of this rare genotype. The phylogenetic analysis indicates a predominance of lineage A variants among HPV67 infections in Japan. Since only 23 complete genome sequences of HPV67 had been obtained until now, the newly determined genome sequences in this study are expected to contribute to further functional and evolutionary studies on the genetic diversity of HPV67.