STING inhibits the reactivation of dormant metastasis in lung adenocarcinoma.

Metastasis frequently develops from disseminated cancer cells that remain dormant after the apparently successful treatment of a primary tumour. These cells fluctuate between an immune-evasive quiescent state and a proliferative state liable to immune-mediated elimination1-6. Little is known about the clearing of reawakened metastatic cells and how this process could be therapeutically activated to eliminate residual disease in patients. Here we use models of indolent lung adenocarcinoma metastasis to identify cancer cell-intrinsic determinants of immune reactivity during exit from dormancy. Genetic screens of tumour-intrinsic immune regulators identified the stimulator of interferon genes (STING) pathway as a suppressor of metastatic outbreak. STING activity increases in metastatic progenitors that re-enter the cell cycle and is dampened by hypermethylation of the STING promoter and enhancer in breakthrough metastases or by chromatin repression in cells re-entering dormancy in response to TGFß. STING expression in cancer cells derived from spontaneous metastases suppresses their outgrowth. Systemic treatment of mice with STING agonists eliminates dormant metastasis and prevents spontaneous outbreaks in a T cell- and natural killer cell-dependent manner-these effects require cancer cell STING function. Thus, STING provides a checkpoint against the progression of dormant metastasis and a therapeutically actionable strategy for the prevention of disease relapse.

Application of high-throughput single-nucleus DNA sequencing in pancreatic cancer.

Despite insights gained by bulk DNA sequencing of cancer it remains challenging to resolve the admixture of normal and tumor cells, and/or of distinct tumor subclones; high-throughput single-cell DNA sequencing circumvents these and brings cancer genomic studies to higher resolution. However, its application has been limited to liquid tumors or a small batch of solid tumors, mainly because of the lack of a scalable workflow to process solid tumor samples. Here we optimize a highly automated nuclei extraction workflow that achieves fast and reliable targeted single-nucleus DNA library preparation of 38 samples from 16 pancreatic ductal adenocarcinoma patients, with an average library yield per sample of 2867 single nuclei. We demonstrate that this workflow not only performs well using low cellularity or low tumor purity samples but reveals genomic evolution patterns of pancreatic ductal adenocarcinoma as well.

Clinico-genomic Characterization of ATM and HRD in Pancreas Cancer: Application for Practice.

PURPOSE: Characterizing germline and somatic ATM variants (gATMm, sATMm) zygosity and their contribution to homologous recombination deficiency (HRD) is important for therapeutic strategy in pancreatic ductal adenocarcinoma (PDAC). EXPERIMENTAL DESIGN: Clinico-genomic data for patients with PDAC and other cancers with ATM variants were abstracted. Genomic instability scores (GIS) were derived from ATM-mutant cancers and overall survival (OS) was evaluated. RESULTS: Forty-six patients had PDAC and pathogenic ATM variants including 24 (52%) stage III/IV: gATMm (N = 24), and sATMm (N = 22). Twenty-seven (59%) had biallelic, 15 (33%) monoallelic, and 4 indeterminate (8%) variants. Median OS for advanced-stage cohort at diagnosis (N = 24) was 19.7 months [95% confidence interval (CI): 12.3-not reached (NR)], 27.1 months (95% CI: 22.7-NR) for gATMm (n = 11), and 12.3 months for sATMm (n = 13; 95% CI: 11.9-NR; P = 0.025). GIS was computed for 33 patients with PDAC and compared with other ATM-mutant cancers enriched for HRD. The median was lower (median, 11; range, 2-29) relative to breast (18, 3-55) or ovarian (25, 3-56) ATM-mutant cancers (P < 0.001 and P = 0.003, respectively). Interestingly, biallelic pathogenic ATM variants were mutually exclusive with TP53. Other canonical driver gene (KRAS, CDKN2A, SMAD4) variants were less frequent in ATM-mutant PDAC. CONCLUSIONS: ATM variants in PDAC represent a distinct biologic group and appear to have favorable OS. Nonetheless, pathogenic ATM variants do not confer an HRD signature in PDAC and ATM should be considered as a non-core HR gene in this disease.

Frequent DYRK2 gene amplification in micropapillary element of lung adenocarcinoma - an implication in progression in EGFR-mutated lung adenocarcinoma.

The present study aimed to discern the molecular alterations involved in the progression of EGFR-mutated lung adenocarcinoma (LADC). We previously demonstrated that the micropapillary (mPAP) element is the most important histological factor for assessing malignant grades in LADCs. Therefore, mPAP and other elements were separately collected from three cases of EGFR-mutated LADC using laser capture microdissection and subjected to a comprehensive mRNA expression analysis. We focused on DYRK2 in this study because its level showed a substantial increase in EGFR-mutated LADCs with mPAP. We also immunohistochemically examined 130 tumors for the expression of DYRK2. The results confirmed a strong expression of DYRK2 in EGFR-mutated LADC with mPAP. Fluorescent in situ hybridization (FISH) analyses targeting the DYRK2 locus revealed frequent gene amplification in EGFR-mutated LADC, specifically occurring in the high-grade components, like mPAP. In summary, the results of this study suggest that DYRK2 overexpression through gene amplification is one of the molecular mechanisms responsible for promoting the progression of EGFR-mutated LADC.

Pulmonary melanocytic nevus - A case report with a mutation analysis of common driver oncogenes.

Nevi are benign melanocytic tumors, and some nevi are considered to develop into malignant melanomas. Most nevi arise in the skin, but nevi occasionally occur in the conjunctiva, esophageal mucosa, or at other sites. Pulmonary melanocytic nevi are extremely rare, and only one case has been reported in the literature. Here, we present a case of pulmonary melanocytic nevus, involving a BRAF gene mutation (V600E), and we discuss the potential significance of this condition as a precursor to pulmonary malignant melanoma.

Unique expression profiles of mucin proteins in interstitial pneumonia-associated lung adenocarcinomas.

In order to clarify idiopathic interstitial pneumonia (IIP)-associated lung adenocarcinoma (LADC), we herein focused on the expression profiles of mucin proteins, the most common cellular differentiation markers. The expression of the mucin (MUC) 1, MUC2, MUC3B, MUC4, MUC5AC, MUC5B, MUC6, MUC7, MUC9, and MUC21 proteins was examined immunohistochemically and their levels were semi-quantified in 80 IIP-associated LADCs and 106 non-IIP LADCs. LADCs were divided into low and high expressers based on thresholds obtained from the receiver operating characteristic (ROC) curves of each mucin protein. Low expressers of MUC1, MUC7, and MUC21 and high expressers of MUC4, MUC5AC, MUC5B, and MUC9 were dominant in the IIP group. Multivariate analyses confirmed that the correlations between mucin expression profiles and IIP-associated LADCs were independent of putative confounding factors, such as smoking, gender, histological types, and cytological types. Thus, the expression profiles of these mucin proteins significantly differed between the IIP and non-IIP groups. IIP-associated LADCs appear to have unique cellular differentiation features and they may develop through a distinct histogenetic pathway. This is the first study to demonstrate that IIP-associated LADCs have unique mucin expression profiles.

Specific expression of MUC21 in micropapillary elements of lung adenocarcinomas - Implications for the progression of EGFR-mutated lung adenocarcinomas.

We investigated the significance of MUC21 in EGFR-mutated lung adenocarcinoma (LADC). Two-hundred forty-one surgically resected LADCs (116 EGFR-mutated and 125 wild-type tumors) were examined for immunohistochemical expression of MUC21 protein. A polyclonal antibody and two monoclonal antibodies (heM21C and heM21D) that bind differentially glycosylated MUC21 epitopes were used, and MUC21 proteins detected by these antibodies were named MUC21P, MUC21C, and MUC21D, respectively. MUC21 mRNA levels were semi-quantified and classified into "high" and "low". Among the immunohistochemical expression detected by three different antibodies, high expressors tended to be related to EGFR mutations. The three varieties of the immunohistochemical expressions were related to different histological elements in the EGFR-mutated LADCs. Either MUC21P or MUC21C high expressors had a higher proportion of lepidic elements with low papillary structure and micropapillary elements. MUC21D high expressors had a significantly higher proportion of micropapillary elements (Mann-Whitney test P ≤0.0001). Furthermore, MUC21D high expressors showed high incidence of lymphatic canal invasion and lymph node metastasis (Pearson x2 test, P = 0.0021, P = 0.0125), and a significantly higher recurrence rate (5-year recurrence-free survival 50.7% vs. 73.8%, log-rank test P = 0.0495). MUC21 proteins with a specific glycosylation status may be involved in the progression of EGFR-mutated LADCs, particularly at the stage where tumors are transforming from pure lepidic to micropapillary through low papillary lepidic lesions.

The Spontaneous Regression of Grade 3 Methotrexate-related Lymphomatoid Granulomatosis: A Case Report and Literature Review.

Lymphomatoid granulomatosis (LYG) is a rare lung disorder diagnosed by radiological imaging of multiple pulmonary nodules and occasionally induced by methotrexate (MTX) use. To date, the treatment of LYG has not been standardized. We herein report the case of a patient with grade 3 MTX-related LYG who presented a bulky lung mass. Importantly, the disease condition only improved after the discontinuation of MTX and remained stable for more than 1 year. Chest physicians should be aware that LYG can develop as a single lung mass and spontaneously regress, even without aggressive chemotherapy, following the cessation of MTX.

A molecular pathological study of four cases of ciliated muconodular papillary tumors of the lung.

Ciliated muconodular papillary tumors (CMPTs) are a recently categorized benign or low-grade malignant neoplasm that develops in the peripheral lung. Only about 40 cases have been reported to date, and the clinicopathological characteristics have yet to be defined in detail. Here, we present four cases of CMPTs with a focus on their immunohistochemical profiles and driver gene mutations. These tumors were a papillary proliferation of a mixture of ciliated, mucous, and basal cells located in the peripheral lung. Ciliated, mucous and basal cells were positive for TTF-1 when using the clone SPT24, but negative for HNF-4α. Basal cells were positive for p40. Mucous cells in some tumors were positive for MUC5AC and MUC6. The Ki-67 index was less than 5%, and strong expression of p53 was not detected. Three of the four tumors had a BRAF (V600E) driver mutation, an EGFR (del E746-T751/S752V) driver mutation, or driver mutations in both EGFR (E709G) and KRAS (G12V). These mutation types are rare for any histological type of lung cancer. The present results confirmed that CMPT is a neoplasm with immunohistochemical features and driver gene mutations that are distinct from those of common lung tumors.

Update on the potential significance of psammoma bodies in lung adenocarcinoma from a modern perspective.

AIMS: Psammoma bodies are concentrically lamellated microscopic structures made of calcium. They are commonly observed in papillary carcinomas of the thyroid gland and serous papillary adenocarcinomas of the ovary, but are also occasionally detected in lung adenocarcinomas. Only one study, published in 1972, has systematically described the significance of psammoma bodies in lung adenocarcinomas. The aim of this study was to update the significance of psammoma bodies in lung adenocarcinomas from a modern perspective. METHODS AND RESULTS: Psammoma bodies were detected in 7.2% (59/822) of the adenocarcinomas examined, among which the papillary (20.3%, 12/59) and acinar (44.1%, 26/59) histological subtypes, with the feature of a terminal respiratory unit (91.5%, 54/59), were dominant. Malignant potential (cell growth activity measured by Ki67 labelling, lymph node metastasis, and postoperative survival) did not significantly differ between adenocarcinomas with and without psammoma bodies. On the basis of cytogenetic features, adenocarcinomas with psammoma bodies were preferentially affected by tyrosine kinase inhibitor (TKI)-targetable driver mutations [EGFR (69.8%, 37/53), ALK (13.2%, 7/53), and ROS1 (1.9%, 1/53)]. Multivariate analyses confirmed that psammoma bodies may constitute an independent predictor for these mutations, particularly EGFR and ALK mutations. CONCLUSIONS: Psammoma bodies may predict a favourable response of lung adenocarcinomas to TKIs.

Relationship between non-TRU lung adenocarcinomas and bronchiolar metaplasia - potential implication in their histogenesis.

Lung adenocarcinomas (ADCs) have been roughly divided into two groups: the terminal respiratory unit (TRU) type and non-TRU type. These ADCs appear to develop through exclusive carcinogenetic pathways because of differences in their cellular morphologies and the profiles of protein expression and genetic alterations. The TRU type develops from atypical adenomatous hyperplasia as a precursor. On the other hand, the histogenesis of the non-TRU type has not yet been defined in detail. We herein investigated histopathological changes in the non-tumor lung tissues of patients with non-TRU-type ADCs in order to define their potential histogenesis. The non-TRU type preferentially occurs in patients with interstitial pneumonia, in whom tumors are located in honeycomb lesions and are associated with bronchiolar metaplasia (BM). Among patients without interstitial pneumonia, non-tumor lung tissues from non-TRU-type ADCs were often affected by multiple BM. In these cases, tumors often were associated with BM. Metaplastic cells adjacent to non-TRU-type ADCs ectopically expressed HNF-4α, a marker for non-TRU-type ADCs. These results suggest that the non-TRU type develops through distinct histogenesis, in which BM is implicated.

The potential significance of alpha-enolase (ENO1) in lung adenocarcinomas - A utility of the immunohistochemical expression in pathologic diagnosis.

We herein analyzed the relationships among the immunohistochemical expression of alpha-enolase (ENO1) and clinicopathological factors in order to define the significance of ENO1 in lung adenocarcinomas (ADCs). ENO1 expression was detected in most of the ADCs examined (95.8%), but not in bronchial and alveolar epithelia. ENO1 expression was typically observed in the cytoplasm among most ADCs (95.8%), but was also detected in the nucleus (56.3%). The levels were significantly higher in terminal respiratory unit (TRU) cytological subtype ADCs. Neither cytoplasmic nor nuclear expression was associated with any other clinicopathological factors including post-operative survival and growth activity. These results suggest that ENO1 is a crucial factor promoting neoplastic transformation exclusively in TRU subtype ADCs. We also investigated the potential utility of the immunohistochemical expression of ENO1 to differentiate TRU-type ADC cells from the reactive hyperplasia of pneumocytes and bronchiolar epithelial cells because difficulties are associated with discriminating these lesions in small biopsy specimens. The sensitivity and specificity of ENO1 (cytoplasmic/nuclear) were 87.5%/37.5% and 88.9%/100%, respectively, which are superior to those of p53 (18.8% and 100%). ENO1 has potential as a biomarker to assist in the histopathological detection of TRU subtype ADC cells.

[A CASE OF XANTHOGRANULOMATOUS PYELONEPHRITIS ASSOCIATED WITH CHROMOPHOBE RENAL CELL CARCINOMA].

Xanthogranulomatous pyelonephritis (XGP) is a type of chronic suppurative renal inflammation. We present an extremely rare case of XGP concomitant with chromophobe renal cell carcinoma (RCC). A-39-year-old woman presented with transient fever and left lower abdominal pain during steroid pulse therapy for thyroid eye disease. Imaging studies including contrast-enhanced computed tomography, magnetic resonance imaging, and doppler ultrasonography, showed a 40 mm unusual mass lesion in the upper pole of the left kidney, and we could not rule out the possibility of malignancy.A left open partial nephrectomy for the renal mass was performed. Pathological examination revealed a 5 mm chromophobe RCC located beside a 30 mm XGP. The patient presented a favorable course without inflammatory episodes or tumor recurrence during the 9-month follow-up. This is the first case report of the coexistent XGP and chromophobe RCC.

The pathological features of idiopathic interstitial pneumonia-associated pulmonary adenocarcinomas.

AIMS: To investigate the pathological features of idiopathic interstitial pneumonia (IIP)-associated pulmonary adenocarcinoma. METHODS AND RESULTS: Surgically resected adenocarcinomas associated with IIP (the IIP group) and adenocarcinomas without IIP (the non-IIP group) were subjected to analysis. Adenocarcinomas in the IIP group were subdivided into two groups: one group included tumours connected to bronchiolar metaplasia in honeycomb lesions (the H-IIP group), and the other included tumours unrelated to honeycomb lesions (the NH-IIP group). Histomorphological appearance and immunohistochemical expression were compared among the H-IIP group, the NH-IIP group, and the non-IIP group. Most of the tumour cells in the H-IIP group had a tall, columnar shape that showed similar features to proximal bronchial epithelium, whereas tumour cells in the NH-IIP group and the non-IIP group had a club-like shape that showed similar features to respiratory bronchiolar/alveolar epithelium. Adenocarcinomas in the H-IIP group tended to be negative for thyroid transcription factor-1 (TTF-1) and positive for hepatocyte nuclear factor-4α (HNF-4α). The frequency of EGFR mutations was significantly lower in adenocarcinomas in the H-IIP group, although the frequencies of KRAS and ALK mutations did not differ among the three groups. CONCLUSIONS: Idiopathic interstitial pneumonia-associated pulmonary adenocarcinomas, especially those arising from honeycomb lesions, have distinct pathological features.

Two surgical cases of thymic MALT lymphoma associated with multiple lung cysts: possible association with Sjögren's syndrome.

Thymic mucosa-associated lymphoid tissue (MALT) lymphoma is rare. Sjögren's syndrome (SjS) has strong association with thymic MALT lymphoma but the exact etiology is unknown. On the other hand, SjS is characterized by the complication of various lung manifestations, including lung cysts. The mechanism for these lesions is also unknown. But the underlying SjS could result in MALT lymphoma with lung cysts. Herein, we demonstrate two surgical cases of thymic MALT lymphoma associated with multiple lung cysts and the characterization of this rare tumor. During surgery, the tumors were found to be well capsuled and had no adhesion or invasion to the surrounding tissues consistent with its characteristics of low grade malignancy. When thymic MALT lymphoma is suspected clinically, video-assisted thoracoscopic surgery might be the best approach for diagnosis. We propose that radiological findings of a thymic tumor along with lung cysts are an indication of thymic MALT lymphoma.

Intraosseous inflammatory myofibroblastic tumor of the mandible with a novel ATIC-ALK fusion mutation: a case report.

BACKGROUND: Inflammatory myofibroblastic tumor (IMT) is a rare low-grade malignant neoplasm with a predilection for children and young adults, and typically arises in the lung, abdominopelvic region, and retroperitoneum. IMTs in the maxillofacial region are extreme rare. Approximately 50% of IMT harbor rearrangements of the anaplastic lymphoma kinase (ALK) gene at 2p23 with various fusion partners. CASE PRESENTATION: We herein report a case of intraosseous IMT of the mandible with a novel ATIC-ALK fusion. Tooth 43 did not erupt after the loss of tooth 83 in an 11-year-old girl with no previous history of trauma. Panoramic tomography showed a unilocular radiolucent lesion in the right anterior mandible resorbing the root of tooth 42 and the medial side of the root of tooth 44. Computed tomography revealed a well- circumscribed 3-cm osteolytic lesion of the right anterior mandible eroding the buccal cortical plate. The entire lesion was curetted out. A histopathological examination revealed the proliferation of plump spindle cells with a storiform architecture and lymphocytes scattered around spindle cells. The spindle cells showed diffuse cytoplasmic staining for ALK by immunohistochemistry. A fluorescence in situ hybridization analysis revealed the translocation of a part of the ALK gene locus at chromosome 2p23. A rapid amplification of cDNA ends analysis confirmed the rearrangement of ALK and identified ATIC as a partner of this ALK fusion mutant. CONCLUSION: To the best of our knowledge, this is the first case of intraosseous IMT of the mandible with a novel ATIC-ALK fusion. We also herein reviewed similar tumors reported in the literature.

A case of severe arthralgia with malignant mesothelioma-associated hypertrophic osteoarthropathy.

Hypertrophic osteoarthropathy (HOA) is a rare syndrome characterized by the abnormal proliferation of dermato-osseous tissue. We report a rare case of malignant mesothelioma-associated HOA who suffered from refractory painful osteoarthropathy. HOA can be associated with malignant mesothelioma and that may be resistant to any treatment.

A Histopathological Feature of EGFR-Mutated Lung Adenocarcinomas with Highly Malignant Potential - An Implication of Micropapillary Element.

The purpose of this study was to define histological features determining the malignant potential of EGFR-mutated lung adenocarcinoma (LADC). Surgically resected tumors (EGFR-mutated LADCs with (21) and without (79) lymph node metastasis and EGFR wild-type LADCs with (26) and without (108) lymph node metastasis) and biopsy samples from inoperably advanced tumors (EGFR-mutated LADCs (78) and EGFR wild-type LADCs (99)) were examined. In surgically resected tumors, the EGFR-mutated LADCs with lymph node metastasis had the micropapillary element in a significantly greater proportion than others (Mann-Whitney tests P ≤0.026). The proportion of micropapillary element was higher in the EGFR-mutated LADC at the advanced stage (stage II, III, or IV) than in the tumor at the early stage (stage I) (Mann-Whitney test, P<0.0001). In the biopsy samples from inoperably advanced LADCs (177), EGFR-mutated tumors also had micropapillary element at a higher frequency than EGFR-wild type tumors (53/78 (68%), versus 30/99 (30%), Pearson x2 test, P<0.0001). In stage I EGFR-mutated LADCs (84), the tumors with the micropapillary element (34) exhibited a significantly higher recurrence rate than tumors without micropapillary element (50) (5-year Recurrence-free survival 64.4% versus 93.3%, log-rank test P = 0.028). The micropapillary element may be an exclusive determinant of malignant potential in EGFR-mutated LADC. It is suggested that EGFR-mutated LADC may develop through a distinct histogenesis, in which the micropapillary element is important for promoting progression.

Alterations in cathepsin L expression in lung cancers.

We herein investigated the potential role of cathepsin L in lung carcinogenesis. Lung cancer cell lines and surgically resected tumors were examined for the expression of the cathepsin L protein and copy number alterations in its gene locus. Cathepsin L was stably expressed in bronchiolar epithelial cells. Neoplastic cells expressed cathepsin L at various levels, whereas its expression was completely lost in most of the lung cancer cell lines (63.6%, 7/11) examined. Furthermore, expression levels were lower in a large fraction of lung tumors (69.5%, 139/200) than in bronchiolar epithelia. The expression of cathepsin L was lost in some tumors (16.0%, 32/200). In adenocarcinomas, expression levels were significantly lower in high-grade tumors than in low-grade tumors (one-way ANOVA, P < 0.0500). Copy number alterations were found in 18.0% (36 [32 gain + 4 loss] /200) of lung tumors. No relationship existed between cathepsin L protein expression levels and the copy number of its gene locus (Spearman's rank-order correlation, P = 0.3096). Collectively, these results suggest that the down-regulated expression of cathepsin L, which is caused by an undefined mechanism other than copy number alterations, is involved in the progression of lung adenocarcinomas.

Promising Effect of Crizotinib on Anaplastic Lymphoma Kinase (ALK)-Positive Non-Small Cell Lung Cancer in an Elderly Patient with a Poor Performance Status: A Case Report and Literature Review.

Crizotinib is highly effective for anaplastic lymphoma kinase (ALK)-positive non-small cell lung cancer (NSCLC). However, it remains unclear whether crizotinib has a beneficial effect on elderly patients with ALK-positive NSCLC with a poor performance status (PS). We herein present the case of an 85-year-old man with stage IV ALK-positive NSCLC, whose PS score was 4 due to pericardial and pleural effusions. After initiating crizotinib therapy, a drastic response was observed and the PS score improved to 0. Adverse effects were manageable. Our results indicate that crizotinib could be an important choice when treating elderly patients with ALK-positive NSCLC with poor PS.