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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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