POU2F3-positive small cell carcinoma of the bladder: A clinicopathologic analysis of 4 cases and literature review.

POU class 2 homeobox 3 (POU2F3)-positive small cell bladder carcinoma (SCBC) is an extremely rare entity, and its clinicopathologic features have not been fully described. Here, we investigated the clinicopathologic features of 4 cases of POU2F3-positive small cell bladder carcinoma (SCBC) and reviewed the literature. We collected 12 cases of SCBC from our departmental archives and detected the expression of POU2F3 by immunohistochemical (IHC) staining. Selected cases with or without POU2F3 expression were subjected to gene expression analysis between two different groups using DESeq2 software. We identified 4 POU2F3-positive SCBC patients, 2 males and 2 females, with a mean age of 77 years. Three patients had hematuria, and 1 patient had dysuria. Radiologic findings showed a bladder mass. Pathologic diagnosis showed that 3 cases were pure SCBC and 1 was mixed urothelial cancer (UC). Histopathologically, four POU2F3-positive SCBC tumors were composed of small round cells with sparse cytoplasm, the nuclei were salt-and-pepper-like or finely granular. Tumor cells showed characteristic cytoplasmic staining with punctate positive signals for cytokeratin. Syn and CD56 were diffusely positive in all the 4 patients. CgA was positive in only one patient. POU2F3-positive SCBC showed higher expression levels of POU2F3, HMGA2 and PLCG2 genes by RNA-Seq. Our data showed the specific clinicopathologic features of 4 rare POU2F3-positive SCBC cases, and the distinct molecular feature was observed between POU2F3-positive and negative SCBC in the limited number of cases.

Primary Cilia Are Frequently Present in Small Cell Lung Carcinomas but Not in Non-Small Cell Lung Carcinomas or Lung Carcinoids.

Most human malignant neoplasms show loss of primary cilia (PC). However, PC are known to be retained and involved in tumorigenesis in some types of neoplasms. The PC status in lung carcinomas remains largely uninvestigated. In this study, we comprehensively assessed the PC status in lung carcinomas. A total of 492 lung carcinomas, consisting of adenocarcinomas (ACs) (n = 319), squamous cell carcinomas (SCCs) (n = 152), and small cell lung carcinomas (SCLCs) (n = 21), were examined by immunohistochemical analysis using an antibody against ARL13B, a marker of PC. The PC-positive rate was markedly higher in SCLCs (81.0%) than in ACs (1.6%) and SCCs (7.9%). We subsequently performed analyses to characterize the PC-positive lung carcinomas further. PC-positive lung carcinomas were more numerous and had longer PC than normal cells. The presence of PC in these cells was not associated with the phase of the cell cycle. We also found that the PC were retained even in metastases from PC-positive lung carcinomas. Furthermore, the hedgehog signaling pathway was activated in PC-positive lung carcinomas. Because ARL13B immunohistochemistry of lung carcinoids (n = 10) also showed a statistically significantly lower rate (10.0%) of PC positivity than SCLCs, we searched for a gene(s) that might be upregulated in PC-positive SCLCs compared with lung carcinoids, but not in PC-negative carcinomas. This search, and further cell culture experiments, identified HYLS1 as a gene possessing the ability to regulate ciliogenesis in PC-positive lung carcinomas. In conclusion, our findings indicate that PC are frequently present in SCLCs but not in non-SCLCs (ACs and SCCs) or lung carcinoids, and their PC exhibit various specific pathobiological characteristics. This suggests an important link between lung carcinogenesis and PC.

[Clinical analysis of 11 patients with neuroendocrine carcinoma in maxillofacial region].

Objective: To investigate the clinicopathological features, treatment and prognosis of maxillofacial neuroendocrine carcinoma. Methods: A total of 11 patients with maxillofacial neuroendocrine carcinoma diagnosed in the Department of Pathology of The First Affiliated Hospital of Zhengzhou University from December 2010 to July 2022 were retrospectively enrolled, including 8 males and 3 females, aged (65.2±9.5) years (ranged from 49 to 87 years), with a disease course of 0.5 to 6.0 months. The clinicopathological data including head and neck CT, MRI and treatment methods were analyzed. Results: Submandibular gland and maxilla were involved in 3 cases, parapharynx in 2 cases, and face, tongue root and soft palate in 1 case respectively. Clinically, the initial symptom is a rapidly growing painless or tender mass, which may be accompanied by restricted mouth opening, dysphagia, and local numbness after invasion of masticatory muscles and nerves. The tumors were all invasive and low-density, with unclear boundaries from the surrounding tissues. Among the patients, 9 received surgical treatment, and 5 received adjuvant treatment after surgery (2 received chemotherapy, 3 received radiotherapy+chemotherapy). According to the 5th edition of the World Health Organization classification of head and neck tumors in 2022, there were 1 case (1/11) with poorly differentiated large cells and 10 cases (10/11) with poorly differentiated small cells. Histologically, the macrocell type is composed of large cells with rough chromatin, obvious vacuolar nucleolus, protruding nucleolus, and necrosis. The small cell type is dominated by small blue round cells with neuroendocrine characteristics, with active growth and multifocal necrosis. Immunohistochemical staining showed that cytokeratin (CK), epithelial membrane antigen (EMA) and synaptophysin (Syn) were diffusively expressed, 10 cases expressed CD56, 8 cases expressed p63, 6 cases expressed weakly punctated chromograin-A (CgA), and S-100 was not expressed. The Ki-67 index ranges from 20 to 90 percent. By the end of follow-up (0.5 to 127.0 months), 3 patients were alive, and the mean progression-free survival (21.0 months) of postoperative chemoradiotherapy patients was significantly longer than that of surgery and/or chemotherapy alone (3.3 months). Conclusions: Maxillofacial neuroendocrine carcinoma is characterized by low differentiation of small cells, high degree of malignancy and poor prognosis. Radical surgery combined with chemoradiotherapy has better local control effect.

Pulmonary cancers across different histotypes share hybrid tuft cell/ionocyte-like molecular features and potentially druggable vulnerabilities.

Tuft cells are chemosensory epithelial cells in the respiratory tract and several other organs. Recent studies revealed tuft cell-like gene expression signatures in some pulmonary adenocarcinomas, squamous cell carcinomas (SQCC), small cell carcinomas (SCLC), and large cell neuroendocrine carcinomas (LCNEC). Identification of their similarities could inform shared druggable vulnerabilities. Clinicopathological features of tuft cell-like (tcl) subsets in various lung cancer histotypes were studied in two independent tumor cohorts using immunohistochemistry (n = 674 and 70). Findings were confirmed, and additional characteristics were explored using public datasets (RNA seq and immunohistochemical data) (n = 555). Drug susceptibilities of tuft cell-like SCLC cell lines were also investigated. By immunohistochemistry, 10-20% of SCLC and LCNEC, and approximately 2% of SQCC expressed POU2F3, the master regulator of tuft cells. These tuft cell-like tumors exhibited "lineage ambiguity" as they co-expressed NCAM1, a marker for neuroendocrine differentiation, and KRT5, a marker for squamous differentiation. In addition, tuft cell-like tumors co-expressed BCL2 and KIT, and tuft cell-like SCLC and LCNEC, but not SQCC, also highly expressed MYC. Data from public datasets confirmed these features and revealed that tuft cell-like SCLC and LCNEC co-clustered on hierarchical clustering. Furthermore, only tuft cell-like subsets among pulmonary cancers significantly expressed FOXI1, the master regulator of ionocytes, suggesting their bidirectional but immature differentiation status. Clinically, tuft cell-like SCLC and LCNEC had a similar prognosis. Experimentally, tuft cell-like SCLC cell lines were susceptible to PARP and BCL2 co-inhibition, indicating synergistic effects. Taken together, pulmonary tuft cell-like cancers maintain histotype-related clinicopathologic characteristics despite overlapping unique molecular features. From a therapeutic perspective, identification of tuft cell-like LCNECs might be crucial given their close kinship with tuft cell-like SCLC.

EZH2 depletion potentiates MYC degradation inhibiting neuroblastoma and small cell carcinoma tumor formation.

Efforts to therapeutically target EZH2 have generally focused on inhibition of its methyltransferase activity, although it remains less clear whether this is the central mechanism whereby EZH2 promotes cancer. In the current study, we show that EZH2 directly interacts with both MYC family oncoproteins, MYC and MYCN, and promotes their stabilization in a methyltransferase-independent manner. By competing against the SCFFBW7 ubiquitin ligase to bind MYC and MYCN, EZH2 counteracts FBW7-mediated MYC(N) polyubiquitination and proteasomal degradation. Depletion, but not enzymatic inhibition, of EZH2 induces robust MYC(N) degradation and inhibits tumor cell growth in MYC(N) driven neuroblastoma and small cell lung carcinoma. Here, we demonstrate the MYC family proteins as global EZH2 oncogenic effectors and EZH2 pharmacologic degraders as potential MYC(N) targeted cancer therapeutics, pointing out that MYC(N) driven cancers may develop inherent resistance to the canonical EZH2 enzymatic inhibitors currently in clinical development.

SMARCA4-Deficient Carcinoma of Uterine Cervix Resembling SCCOHT-Case Report.

Small cell carcinoma of hypercalcemic type (SCCOHT) is a rare gynaecological neoplasm, originating mostly in the ovaries. Cervical origin of this very aggressive malignancy with unknown histogenesis is an extremely rare condition, without published management recommendations. Alterations in SMARCA4 gene are supposed to play the major role in SCCOHT oncogenesis and their identification is crucial for the diagnosis. Adequate genetic counselling of the patients and their families seems to be of great importance. Optimal management and treatment approaches are not known yet but may extremely influence the prognosis of young female patients that suffer from this very resistant disease. Nowadays, a translational research seems to be the key for the further diagnostic and treatment strategies of SCCOHT. The purpose of the case report is to provide practical information and useful recommendations on the diagnosis, management, and treatment of SMARCA4-deficient carcinoma of the uterine cervix resembling SCCOHT.

Delineating the Molecular Events Underlying Development of Prostate Cancer Variants with Neuroendocrine/Small Cell Carcinoma Characteristics.

The treatment landscape of prostate cancer has changed dramatically following the advent of novel systemic therapies, most of which target the androgen receptor (AR). Agents such as abiraterone, enzalutamide, apalutamide, darolutamide were designed to further suppress androgen receptor signaling following gonadal suppression achieved by first-line androgen deprivation therapies. These potent AR targeting agents are increasingly used in the earlier stages of the disease spectrum with the goal of delaying disease progression and extending survival. Although these therapies are effective in controlling prostate tumors dependent on or addicted to AR signaling, prostate tumors surviving the onslaught of potent treatments may evolve and develop drug resistance. A substantial proportion of treatment failures can be explained by the development of treatment-induced aggressive prostate cancer variants such as neuroendocrine/small cell carcinoma. These emerging disease entities demand detailed characterization and precise definitions. We postulate that these treatment-induced prostate cancer entities should be defined molecularly to overcome the drawbacks associated with the current clinical and pathological definitions. A precise molecular definition conforms with current knowledge on the molecular evolution of this disease entity and will enable early detection and early intervention.

The prognostic value of TCF1+CD8+T in primary small cell carcinoma of the esophagus.

TCF1+CD8+T cells are reported to exhibit stem-like properties with the ability to self-renew and differentiate into terminal effector T cells (TCF1-CD8+T cells) to enhance antitumor response. Previous studies indicated that TCF1+CD8+ tumor-infiltrating lymphocytes (TILs) are related to response to immunotherapy. However, their role in predicting prognosis for patients with primary small cell carcinoma of the esophagus (PSCCE) remains unclear. In this study, the expression of TCF1+CD8+T was analyzed by multiplex fluorescence immunohistochemistry in tumor tissues of 79 patients with PSCCE. High infiltration of TCF1+CD8+T cells had longer overall survival (OS) than low infiltration (P = .009, hazard ratio [HR] = 0.506). High TCF1+CD8/CD8 ratio (>21%) showed superior OS compared with low ratio (≤21%) (P < .001, HR = 0.394). In the validation set (n = 20), the prognostic value of TCF1+CD8+T cells on OS was also verified. TCF1+CD8+T cells are strong prognostic predictors.

Small Cell Carcinoma of the Ovary, Hypercalcemic Type, in a 12-Month-Old Girl.

Small cell carcinoma of the ovary, hypercalcemic type (SCCOHT) is a highly aggressive malignant tumor affecting predominantly young adults and adolescents with an average age of 23.9 at time of diagnosis. Up to two thirds of patients have paraneoplastic hypercalcemia. The molecular signature of these tumors is SMARCA4 mutations, with somatic and germline pathogenic variants previously described. We report a case of a previously healthy one-year-old girl who was noticed to have mild anemia and an abdominal mass during a well-child visit. Further laboratory testing revealed hypercalcemia. A computerized tomography scan showed a left-sided ovarian mass (9.3 x 7.3 x 7 cm). The resection specimen showed a large ovarian tumor with solid tan-yellow cut surfaces and small foci of necrosis. Microscopically, the tumor was composed of sheets of small, hyperchromatic epithelioid cells with focal rhabdoid large cell morphology. The tumor cells were strongly and diffusely positive for WT1 (N-terminal antibodies) with focal EMA and Pan-keratin positivity. Absent SMARCA4 (BRG1) protein expression by immunohistochemistry ultimately established the diagnosis of small cell carcinoma of the ovary, hypercalcemic type. To our knowledge, this is the youngest patient reported in the literature.

Heterogenous chemosensitivity of a panel of organoid lines derived from small cell neuroendocrine carcinoma of the uterine cervix.

Small cell neuroendocrine carcinoma (SCNEC) of the uterine cervix is a rare disease with a poor prognosis. The lack of established disease models has hampered therapy development. We generated a panel of cancer tissue-originated spheroid (CTOS) lines derived from SCNEC of the uterine cervix using a method based upon cell-cell contact throughout the preparation and culturing processes. Using 11 CTOS lines, we assessed the sensitivity of various drugs used in clinical practice. Drug sensitivity assays revealed significant heterogeneous inter-CTOS chemosensitivity. Microarray analyses were then performed to identify sensitivity-related gene signatures. Specific gene sets were identified which likely contribute to the sensitivity to the tested drugs. We identified a line (Cerv54) that was exceptionally sensitive to irinotecan. Cerv54 had increased levels of CES1, which catalyzes the conversion of irinotecan to the active form, SN38, although in Cerv54 cells, SN38 was undetectable, CES1 expression and activity were markedly low compared to the liver, and a CES1 inhibitor had no effect on irinotecan sensitivity. These results suggested a novel irinotecan mode of action in Cerv54. Our CTOS lines may be useful for understanding the variation and mechanism of drug sensitivity, contributing to the understanding and development of chemotherapeutic drugs.

Extrapulmonary Small Cell Cancer: A New Insight into a Rare Disease.

INTRODUCTION: Extrapulmonary small-cell cancer (EPSCC) is a relatively rare malignancy. The management of EPSCC is usually extrapolated from small-cell lung cancer (SCLC). In spite of the morphological similarity of the 2 malignancies, there are many differences in clinical features, prognosis, and recommendations of treatment of these disorders. The data on the correlation of clinical-pathological characteristics of EPSCC and treatment results is scarce. MATERIALS AND METHODS: This retrospective analysis of 41 consecutively treated patients diagnosed with EPSCC in 2015-2018 was performed in a tertiary medical center. The correlation between the clinical and pathological characteristics and the treatment outcome (response rate, disease-free interval, and overall medial survival) was done using the standard statistics, Kaplan-Meier method, and multivariate analyses. The stratification was done on the stage of the disease, Ki-67 proliferative index, the location of the tumor, and smoking. RESULTS: Forty-one patients were included with a median age of 66.3 years. The most common primary site was the gastrointestinal tract (28, 68.3%) including the pancreas. The most common distant metastasis site was the liver (23, 56.1%). Only 2 patients (4.9%) had brain metastases. Unlike in SCLC, most patients did not have any history of smoking (23, 56.1%). Nineteen patients with metastatic disease received systemic treatment, mostly cisplatin-based chemotherapy, with a response rate of 57.9%. The results of treatment were significantly better in patients with disseminated EPSCC with Ki-67 <55%, while its role in limited disease was nonsignificant. DISCUSSION: The results of our study show the unique entity of EPSCC. The rarity of brain metastases proves that prophylactic brain irradiation should not be recommended in practice. The provocative idea of prophylactic liver irradiation in limited-stage EPSCC of gastrointestinal origin can be evaluated in future studies. The predictive role of Ki-67 is important in metastatic EPSCC. There is probably no role of smoking in developing EPSCC.

SMARCA4 (BRG1) and SMARCB1 (INI1) expression in TTF-1 negative neuroendocrine carcinomas including merkel cell carcinoma.

SMARCA4 and SMARCB1 loss of function has been implicated in many different tumors. The objective of this study was to investigate the loss of BRG1 and INI1 expression in TTF-1 negative neuroendocrine carcinomas to see if they are analogous to small-cell carcinoma of the ovary, hypercalcemic type. The potential role of these tumor suppressor genes in high-grade neuroendocrine carcinoma largely remains unknown. Cases of previously diagnosed Small cell carcinoma (SmCC), Large cell neuroendocrine carcinoma (LCNEC) and Merkel cell carcinoma (MCC) were selected. Immunohistochemical expression patterns for BRG1 and INI1 were interpreted as: intact, hybrid and complete loss of nuclear staining. SmCC and LCNEC cases were divided as TTF-1 positive and TTF-1 negative subsets. One case of TTF-1 negative SmCC (lung) showed loss of SMARCA4(BRG1) expression. Amongst TTF-1 negative LCNEC, one case (lung) showed complete loss of SMARCA4(BRG1) and partial loss of SMARCB1(INI1) and one case (lymph node) had hybrid expression of SMARCA4(BRG1) with intact SMARCB1(INI1) expression. All TTF-1 positive cases and all MCC cases showed intact expression of SMARCA4(BRG1) and SMARCB1(INI1). Our study highlights that SMARCA4(BRG1) is deficient in a subset of NEC. Inactivation of SMARCA4 in a subset of TTF-1 negative neuroendocrine carcinomas especially of pulmonary site can be further studied for their therapeutic response to targeted therapy e.g. EZH2 inhibitors. In addition, our study is the first to show that BRG1 and INI1 expression are intact in MCC and hence the biology of MCC might be completely exclusive of these two tumor suppressor genes.

p16 immunostaining in cytology specimens: its application, expression, interpretation, and challenges.

INTRODUCTION: p16 immunostaining is considered as a surrogate marker for human papillomavirus (HPV)-related head and neck squamous cell carcinomas (HNSCC). Herein, the utility of p16 is evaluated in cytology specimens. MATERIAL AND METHODS: The electronic data of a large academic institution was searched for cytology cases accompanied by p16 (2014-2018). Cases were categorized based on body sites. P16 staining was quantified (negative [0%], focal/patchy, or diffusely positive [>70%]). HPV testing was correlated where available. RESULTS: A total of 372 cases were included (male:female, 239:133). The largest differences in application of p16 between men and women were in head/neck cases (209 versus 59) and the abdominal cases (1 versus 33), respectively. p16 diffuse staining is seen in most squamous cell carcinomas, small cell carcinomas, and gynecologic serous carcinomas. p16 expression was patchy or negative in most adenocarcinoma, neuroendocrine carcinoma, spindle cell neoplasms, and benign conditions. HPV testing was done on 217 cases including 138 cases with strong p16 (127 HPV+/11 HPV-), 20 cases with focal/patchy P16 staining (6 HPV+/14 HPV-) and 59 cases with negative p16 staining (3 HPV+/56 HPV-). CONCLUSIONS: Diffuse p16 staining aids in the diagnosis of HPV-related carcinomas, particularly HPV-related HNSCC, across the body and according to sex. In contrast, focal/patchy p16 staining does not correlate with HPV status across various body sites. In conclusion, intensity of p16 matters and should be correlated with cytomorphology, clinical history, and ancillary studies (eg, p40 immunostaining) for an accurate diagnosis and preventing diagnostic pitfalls.

Recombinant Adeno-associated Virus 9-mediated Expression of Kallistatin Suppresses Lung Tumor Growth in Mice.

BACKGROUND: Lung cancer remains the most common cause of cancer-related deaths in China and worldwide. Traditional surgery and chemotherapy do not offer an effective cure, although gene therapy may be a promising future alternative. Kallistatin (Kal) is an endogenous inhibitor of angiogenesis and tumorigenesis. Recombinant adeno-associated virus (rAAV) is considered the most promising vector for gene therapy of many diseases due to persistent and long-term transgenic expression. OBJECTIVE: The aim of this study was to investigate whether rAAV9-Kal inhibited NCI-H446 subcutaneous xenograft tumor growth in mice. METHODS: The subcutaneous xenograft mode was induced by subcutaneous injection of 2×107 H446 cells into the dorsal skin of BALB/c nude mice. The mice were administered with ssrAAV9-Kal (single- stranded rAAV9) or dsrAAV9-Kal (double-stranded rAAV9) by intraperitoneal injection (I.P.). Tumor microvessel density (MVD) was examined by anti-CD34 staining to evaluate tumor angiogenesis. RESULTS: Compared with the PBS (blank control) group, tumor growth in the high-dose ssrAAV9-Kal group was inhibited by 40% by day 49, and the MVD of tumor tissues was significantly decreased. CONCLUSION: The results indicate that this therapeutic strategy is a promising approach for clinical cancer therapy and implicate rAAV9-Kal as a candidate for gene therapy of lung cancer.

Immune receptor inhibition through enforced phosphatase recruitment.

Antibodies that antagonize extracellular receptor-ligand interactions are used as therapeutic agents for many diseases to inhibit signalling by cell-surface receptors1. However, this approach does not directly prevent intracellular signalling, such as through tonic or sustained signalling after ligand engagement. Here we present an alternative approach for attenuating cell-surface receptor signalling, termed receptor inhibition by phosphatase recruitment (RIPR). This approach compels cis-ligation of cell-surface receptors containing ITAM, ITIM or ITSM tyrosine phosphorylation motifs to the promiscuous cell-surface phosphatase CD452,3, which results in the direct intracellular dephosphorylation of tyrosine residues on the receptor target. As an example, we found that tonic signalling by the programmed cell death-1 receptor (PD-1) results in residual suppression of T cell activation, but is not inhibited by ligand-antagonist antibodies. We engineered a PD-1 molecule, which we denote RIPR-PD1, that induces cross-linking of PD-1 to CD45 and inhibits both tonic and ligand-activated signalling. RIPR-PD1 demonstrated enhanced inhibition of checkpoint blockade compared with ligand blocking by anti-PD1 antibodies, and increased therapeutic efficacy over anti-PD1 in mouse tumour models. We also show that the RIPR strategy extends to other immune-receptor targets that contain activating or inhibitory ITIM, ITSM or ITAM motifs; for example, inhibition of the macrophage SIRPα 'don't eat me' signal with a SIRPα-CD45 RIPR molecule potentiates antibody-dependent cellular phagocytosis beyond that of SIRPα blockade alone. RIPR represents a general strategy for direct attenuation of signalling by kinase-activated cell-surface receptors.

Diagnostic value of four neuroendocrine markers in small cell neuroendocrine carcinomas of the cervix: a meta-analysis.

Small cell neuroendocrine carcinoma of the cervix (SCNECC) is a highly invasive cervical cancer. The immunohistochemical criteria is an important aspect for assistant diagnosis of SCNECC. However, which markers can be appropriate selection for diagnosing SCNECC were not determined. The aim was to systematically evaluate expression levels of four neuroendocrine markers (containing synaptophysin (Syn), neural cell adhesion molecules (CD56), neuron-specific enolase (NSE) and chromograninA (CgA)) and to find out the appropriate selection for diagnosing SCNECC. Four English and three Chinese libraries were retrieved between 1984 and 2020. 23 studies about NSE, 36 studies about Syn, 23 studies about CD56 and 36 studies about CgA (all studies containing 581 patients) were eligible for meta-analyses. The pooled positive expression percentages (95% CI; I2) were as follows: 84.84% (79.41-90.27%; 76.7%) for Syn, 84.53% (79.43-89.96%; 37.5%) for CD56, 77.94% (69.13-86.76%; 83.5%) for NSE, and 72.90% (67.40-78.86%; 59.7%) for CgA. The positive proportions (95% CI; I2) ranked top three of simultaneous expressions of two markers were 87.75% (82.03-93.87%, 33.3%) for Syn and CD56, 70.92% (50.50-87.68%, 82.7%) for Syn and NSE, 65.65% (53.33-76.98%, 73.5%) for Syn and CgA. This confirms that Syn and CD56 are reliable indicators for diagnosing SCNECC.

Neuroendocrine differentiation in usual-type prostatic adenocarcinoma: Molecular characterization and clinical significance.

BACKGROUND: Small cell neuroendocrine (NE) carcinomas of the prostate classically lose androgen receptor (AR) expression, may harbor loss of the RB1, TP53, and PTEN tumor suppressor genes, and are associated with a poor prognosis. However usual-type adenocarcinomas may also contain areas of NE differentiation, and in this context the molecular features and biological significance are less certain. METHODS: We examined the molecular phenotype and oncologic outcomes of primary prostate adenocarcinomas with ≥5% NE differentiation (≥5% chromogranin A-positive NE cells in any given tumor spot on tissue microarray) using three independent study sets: a set of tumors with paneth cell-like NE differentiation (n = 26), a retrospective case-cohort of intermediate- and high-risk patients enriched for adverse outcomes (n = 267), and primary tumors from a retrospective series of men with eventual castration-resistant metastatic prostate cancer (CRPC) treated with abiraterone or enzalutamide (n = 55). RESULTS: Benign NE cells expressed significantly lower quantified AR levels compared with paired benign luminal cells (P < .001). Similarly, paneth-like NE carcinoma cells or carcinoma cells expressing chromogranin A expressed significantly lower quantified AR levels than paired non-NE carcinoma cells (P < .001). Quantified ERG protein expression, was also lower in chromogranin A-labeled adenocarcinoma cells compared with unlabeled cells (P < .001) and tumors with NE differentiation showed lower gene expression scores for AR activity compared with those without. Despite evidence of lower AR signaling, adenocarcinomas with NE differentiation did not differ by prevalence of TP53 missense mutations, or PTEN or RB1 loss, compared with those without NE differentiation. Finally, NE differentiation was not associated with time to metastasis in intermediate- and high-risk patients (P = .6 on multivariate analysis), nor with progression-free survival in patients with CRPC treated with abiraterone or enzalutamide (P = .9). CONCLUSION: NE differentiation in usual-type primary prostate adenocarcinoma is a molecularly and clinically distinct form of lineage plasticity from that occurring in small cell NE carcinoma.

Interferon-Induced Transmembrane Protein 1 (IFITM1) Promotes Distant Metastasis of Small Cell Lung Cancer.

Small cell lung cancer (SCLC) is a severe malignancy associated with early and widespread metastasis. To study SCLC metastasis, we previously developed an orthotopic transplantation model using the human SCLC cell line DMS273. In the model, metastatic foci were found in distant tissues such as bone and the adrenal gland, similarly as observed in patients with SCLC. In this study, we evaluated the differentially expressed genes between orthotopic and metastatic tumors in the model. We isolated tumor cells from orthotopic and metastatic sites, and the tumor cell RNA was analyzed using DNA microarray analysis. We found that 19 genes in metastatic tumors were upregulated by more than 4-fold compared with their expression in orthotopic tumors. One of these genes encodes a transmembrane protein, interferon (IFN)-induced transmembrane protein 1 (IFITM1), and immunohistochemical analysis confirmed the higher expression of the protein in metastatic sites than in orthotopic sites. IFITM1 was also detected in some SCLC cell lines and lung tumors from patients with SCLC. The overexpression of IFITM1 in DMS273 cells increased their metastatic formation in the orthotopic model and in an experimental metastasis model. Conversely, the silencing of IFITM1 suppressed metastatic formation by DMS273 cells. We also found that IFITM1 overexpression promoted the metastatic formation of NCI-H69 human SCLC cells. These results demonstrate that IFITM1 promotes distant metastasis in xenograft models of human SCLC.

TTF-1 Positive Primary Small Cell Carcinoma of the Breast: A Case Report and Review of the Literature.

Primary small cell carcinoma of the breast (SCCB) is a rare tumor subtype comprising <0.1% of all breast carcinomas. Here we present a case of thyroid transcription factor-1 (TTF-1) positive SCCB that recurred within 3 years of diagnosis in the lung and lymph nodes. Given the small number of cases, no clear guidelines exist on the appropriate management of patients with these aggressive tumors. We present a case study and review the current literature to highlight the knowledge gaps and needs of patients with these rare tumors. A 50-year-old premenopausal woman with no family history, presented with a palpable right breast mass. Biopsy was consistent with primary SCCB that was poorly differentiated, positive for synaptophysin and chromogranin and TTF-1 and presence of ductal carcinoma in situ component showing neuroendocrine differentiation. Imaging with PET, CT, and MRI brain excluded any other sites of primary disease. She underwent a right lumpectomy with axillary lymph node dissection and was treated with adjuvant cisplatin-based chemotherapy and concurrent radiation therapy. Thirty-four months later, routine scans showed a new right lower-lobe lung nodule and an enlarged sub-carinal node that was proven to be poorly differentiated neuroendocrine cancer. This case report sheds light on a rarely described disease and provides a comprehensive approach to diagnosis and management. Primary SCCB is an extremely rare, aggressive form of breast cancer that is molecularly and histologically similar to SCLC. However, a review of the literature highlights recent mutational analyses that show important differences between these two cancer types, including an increase in PIK3CA mutations in primary SCCB. Further studies, including genomic analyses are needed to better define this malignancy and to develop a standard treatment.

Lung nuclear protein in testis carcinoma in an elderly Korean woman: A case report with cytohistological analysis.

Nuclear protein in testis (NUT) carcinoma is a rare, aggressive carcinoma that is a diagnostic challenge for pathologists. Here, we report a case of NUT carcinoma in a 63-year-old woman with uncommon immunohistochemical results. The initial bronchoscopic biopsy revealed a poorly differentiated carcinoma with p63 immunohistochemical stain positivity. However, the cytomorphological features of the pleural fluid were unusual. Immunohistochemical staining of the pleural fluid revealed diffuse positivity for vimentin and focal positivity for cytokeratin and neuroendocrine markers. Because of chemoresistance, other malignancies, including sarcomatoid carcinoma, combined small cell carcinoma, and an unusual form of NUT carcinoma, were considered as differential diagnoses. The diagnosis of NUT carcinoma was confirmed using NUT-specific antibodies and fluorescence in situ hybridization. The current case was a diagnostic challenge because of the poorly differentiated cytomorphology and uncommon immunohistochemical results. Pathologists and clinicians should consider NUT carcinoma in the differential diagnosis, as this malignancy has a dismal prognosis and needs to be diagnosed accurately for the most effective treatment. KEY POINTS: Metastatic NUT carcinoma can show diffuse vimentin positivity and focal neuroendocrine marker positivity. NUT carcinoma can be misdiagnosed as basaloid squamous cell carcinoma in routine diagnosis, especially in older-aged patients. This study was a diagnostic challenge because of the poorly differentiated cytomorphology and uncommon immunohistochemical results for NUT carcinoma. Pathologists should differentially diagnose NUT carcinoma when rare cytohistological features are observed at any age.