Squamous Cell Markers Research Articles

Sinonasal Squamous Cell Carcinoma with DEK::AFF2 Rearrangement : An Aggressive Cancer with Bland Morphology.

DEK::AFF2 squamous cell carcinoma is a recently described cancer entity, with 29 cases reported to date. Occasionally, these carcinomas appear deceptively indistinguishable; however, specific morphological and phenotypic features suggest the presence of this rearrangement. However, the prognostic value of this diagnosis remains unclear. We aimed to report a new case series with histological, molecular, and clinical features. We collected data from 15 patients and investigated their phenotypes, including the expression profiles of CK7, P63/P40, PDL1, AFF2, and P16, morphological features, and associated prognostic data. We analyzed these data along with the previously published data. Most of these cases exhibited indicative morphological features, such as exophytic and endophytic papillary growth, nuclear monomorphism, and abundant neutrophil-rich inflammatory infiltrates. Immunohistochemical analysis revealed the expression of AFF2 and squamous cell markers in all the patients. Overexpression of P16 was not detected, whereas CK7 and PDL1 were expressed variably. In our study cohort, a 50% progression or recurrence rate, 25% lymph node metastasis, 17% distant metastasis, and 18% disease-related death were identified, with a short follow-up time. DEK::AFF2 squamous cell carcinoma incidence is probably underestimated. The low-grade appearance of these tumors sometimes limits their detection. The rates of recurrence and metastasis seem to be high despite an often bland morphology. We propose AFF2 immunohistochemistry as an effective tool, and a diagnostic algorithm has been established to support accurate diagnosis of these tumors.

Study of p40 is superior to p63 for the diagnosis of pulmonary squamous cell carcinoma on cytological smears

Background: Histology and genetically driven management are the current standard in carcinoma lung. Adequate tissue is a challenge in a few cases. While liquid biopsy is an, it’s an always preferred to get an initial cyto/histo morphological confirmation. While the immune-histo chemistry (IHC) is a proven method to differentiate the squamous vs adeno carcinoma, the role of various “immuno-cyto-chemical” makers were not studied widely. Methods: This is a retrospective (July 2018 to December 2018) for random sample collection and prospective (Jan 2019-August 2019) study conducted from in the Department of pathology, govt. chest hospital Osmania medical college, Hyderabad as a part of PG dissertation, 120 subjects with cytological diagnosis of non-small cell lung carcinoma were analyzed during this period and others were excluded. Results: Out of 120 cases 80-adenocarcinoma (ADC) and 40-squamous cell carcinoma (SCC). Most of the patients are in 61-70 years, 20 are 71-80 years, 20 between 51-60 and 10 are between 40-50 years. In this study sensitivity of p63 and p40 is equal, but specificity and positive predictive value are higher for p40 for diagnosis of SCC. Conclusions: Immuno-cyto-chemistry is still a valid option in selected cases where getting a biopsy is difficult. Our findings recommend the use of p40 immuno staining rather than p63 as a squamous cell marker.

Neuroendocrine and squamous cell phenotypes of NUT carcinoma are potential diagnostic pitfalls that discriminating it from mimickers, such as small cell and squamous cell carcinoma

IntroductionNUT carcinoma is a rare cancer associated with a poor prognosis. Because of its rarity, its diagnosis is challenging and is usually made by excluding other diagnoses. Immunohistochemical analysis is a reliable technique that contributes to a correct diagnosis, but overestimating the expression of neuroendocrine (NE) markers may result in an incorrect diagnosis. In this study, we established the immunohistochemical phenotypes of NUT carcinoma compared with tumors that mimic its phenotype to identify potential diagnostic pitfalls.MethodsEight cases of NUT carcinoma were examined along with eight basaloid squamous cell carcinomas and thirteen cases of small cell carcinoma using an immunohistochemical panel consisting of various antibodies.ResultsOf the eight NUT carcinomas, three patients had a smoking history. All the cases examined for INSM1 were positive (6/6, 100%), although the staining was somewhat weak. Among the NE markers, synaptophysin was variably positive in two NUT carcinomas (2/6, 33%); however, all cases were negative for ASCL1, chromogranin A, and CD56. Moreover, the squamous cell markers, p40 and CK5/6, were weakly expressed in 4/6 (67%) and 3/6 (50%) of the NUT carcinomas, respectively.ConclusionsFor tumors with an ambiguous morphology, applying the neuroendocrine phenotype of NUT carcinoma may be misleading; particularly, when distinguishing it from small-cell carcinoma. Similarly, null or weak expression of squamous cell markers may be observed in NUT carcinoma, but this differs from squamous cell carcinoma, which consistently demonstrates strong positivity for squamous cell markers.

Nuclear Protein in Testis (NUT) Carcinoma: A Comprehensive Immunohistochemical Analysis of 57 Cases With Consideration of Interpretation and Pitfall Recognition.

Nuclear protein in testis (NUT) carcinoma is an aggressive carcinoma defined by NUTM1 gene rearrangement. Diagnostic challenges include morphologic overlap with poorly differentiated squamous cell carcinoma, small cell carcinoma, thoracic SMARCA4-deficient undifferentiated tumor, and other small round blue cell tumors. To comprehensively study the immunohistochemistry (IHC) features of a large cohort of NUT carcinomas. Fifty-seven NUT carcinoma cases were identified from 2012-2022, including 38 thoracic/mediastinal, 13 head and neck/sinonasal, and 6 from other sites. Pathology reports and available slides were reviewed. Comprehensive IHC studies were performed on available cases. Keratin stains showed variable positivity and were entirely negative in 15% (8 of 55) of cases. p40 was only positive in 65% (24 of 37) of cases, implying inferior sensitivity when compared to p63 (87% sensitivity, 20 of 23 cases) and other squamous cell markers. Neuroendocrine markers were focally/weakly positive in few cases; however, INSM1 was positive in 54% (7 of 13) of cases, indicating a possible diagnostic pitfall. TTF-1 was mostly negative with focal positivity in 26% (10 of 38) of cases. Occasional CD34 (15%, 3 of 20 cases) and CD99 (21%, 3 of 14 cases) positivity could also cause potential diagnostic confusion. S100, desmin, CD45, and SALL4 were rarely positive. BRG1 and INI1 were retained in all cases. Ki-67 proliferative index was high (median, 60%). PD-L1 was negative in all tested cases. This comprehensive IHC study demonstrates the immunohistochemical spectrum of NUT carcinoma. The findings can help narrow the differential diagnosis and recognize potential pitfalls.

Endometrial serous carcinoma with extensive squamous differentiation mimicking primary endometrial squamous cell carcinoma: Clinicopathological and molecular analysis of a case with literature review

In the histological assessment of endometrial carcinoma, the presence of squamous differentiation is generally considered inconsistent with a serous histotype. Herein, we report a case of endometrial serous carcinoma with extensive squamous differentiation mimicking squamous cell carcinoma, with literature review.A 67-years-old-woman underwent hysterectomy, bilateral salpingo-oophorectomy, sentinel lymph node resection, omental and peritoneal biopsies, due to a 8cm endometrial mass. Histologically, the tumor showed squamous carcinoma features with positivity for squamous cell markers (p40, p63, cytokeratin-5/6, cytokeratin-34βE12) and negativity for Müllerian markers (PAX8, estrogen receptor, progesterone receptor). No immunohistochemical/molecular alterations typical ofendometrioid carcinoma (i.e., PTEN loss, mismatch repair deficiency, nuclear β-catenin expression,POLEmutation) were observed. P53 showed aberrant pattern and p16 showed basal positivity. The tumor infiltrated the myometrium full-thickness with extensive lymphovascular space invasion. Surprisingly, the sentinel lymph node metastasis showed overt serous carcinoma features. Additional sampling of the endometrial mass revealed a minor. In conclusion, serous carcinoma may show diffuse squamous differentiation. In the case of suspected primary endometrial squamous cell carcinoma, an extensive sampling is warranted.

Abstract 921: The Nrf2E79Q activating mutation accelerates growth of pure-small cell lung cancer but not combined small cell lung cancer Tp53floxed/floxed/Cdkn2afloxed/floxed mice

Abstract Inactivating mutations in TP53/P16 are found in most types of non-small cell lung cancer while RB1/P16 losspredominates in small cell lung cancer (SCLC). NRF2 activating mutations are also found frequently in lungcancer, especially in lung squamous cell carcinoma. However, how concurrent mutations in these genes maycontribute to lung cancer development is not fully understood. To address this problem, we compared lung tumordevelopment in a genetically-engineered mouse model (GEMM) with dual Trp53/p16 deficiency, +/- expressionof one of the most common mutations in NRF2 found in human tumors, Nrf2E79Q/+. Surprisingly, both groups,Nrf2E79Q/+ and Nrf2+/+, developed combined-SCLC (C-SCLC): a mixture of SCLC and large cell neuroendocrine(NE) carcinoma along with pure-SCLC (P-SCLC). The appearance of C-SCLC implicates Trp53/p16 double lossin the development of this type of lung cancer. Both groups developed C-SCLC at the same penetrance andincidence; all tumors labeled positive for NE-markers by immunohistochemistry (IHC) including ASCL1, SYP andINSM1. However, C-SCLCs developed by Nrf2E79Q/+ mice did not show NRF2 labeling by IHC, despiterecombination of the Nrf2E79Q/+ allele. In contrast, the Nrf2E79Q/+ mice showed significantly higher incidence of P-SCLC compared to Nrf2+/+ mice. All P-SCLC from Nrf2E79Q/+ mice were NRF2-positive by IHC, while the fewtumors developed by Nrf2+/+ mice were negative. All P-SCLC lesions labeled positive for NE-markers includingASCL1, CGRP & SYP. Both C-SCLCs & P-SCLCs were positive for NKX1.2 (lung cancer-marker) and negativefor P63 (squamous cell-marker). Interestingly, phospho-RB1 was positive for both C-SCLCs & P-SCLCs,suggesting the loss of p16 in our GEMM inactivates Rb1 through loss of inhibition of the cyclin dependent kinases4/6 (CDK4/6). This is the first study showing that the concurrent inactivation of Trp53/p16 in mice drivesdevelopment of C-SCLC. Our study also implicated activation of NRF2 signaling in the progression of SCLC.Our next studies will dissect the mechanisms by which NRF2 activation contributes to the development of SCLCdevelopment. Citation Format: Samera Hamad, Stephanie A. Montgomery, Jeremy M. Simon, Brittany M. Bowman, Kyle B. Spainhower, Ryan M. Murphy, Agnieszka Witkiewicz, Suzanne E. Fenton, Scott H. Randell, Neil Hayes, Erik Knudsen, Trudy G. Oliver, Ben Major, Bernard E. Weissman. The Nrf2E79Q activating mutation accelerates growth of pure-small cell lung cancer but not combined small cell lung cancer Tp53floxed/floxed/Cdkn2afloxed/floxed mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 921.

TP53, CDKN2A/P16, and NFE2L2/NRF2 regulate the incidence of pure- and combined-small cell lung cancer in mice.

Studies have shown that Nrf2E79Q/+ is one of the most common mutations found in human tumors. To elucidate how this genetic change contributes to lung cancer, we compared lung tumor development in a genetically-engineered mouse model (GEMM) with dual Trp53/p16 loss, the most common mutations found in human lung tumors, in the presence or absence of Nrf2E79Q/+. Trp53/p16-deficient mice developed combined-small cell lung cancer (C-SCLC), a mixture of pure-SCLC (P-SCLC) and large cell neuroendocrine carcinoma. Mice possessing the LSL-Nrf2E79Q mutation showed no difference in the incidence or latency of C-SCLC compared with Nrf2+/+ mice. However, these tumors did not express NRF2 despite Cre-induced recombination of the LSL-Nrf2E79Q allele. Trp53/p16-deficient mice also developed P-SCLC, where activation of the NRF2E79Q mutation associated with a higher incidence of this tumor type. All C-SCLCs and P-SCLCs were positive for NE-markers, NKX1-2 (a lung cancer marker) and negative for P63 (a squamous cell marker), while only P-SCLC expressed NRF2 by immunohistochemistry. Analysis of a consensus NRF2 pathway signature in human NE+-lung tumors showed variable activation of NRF2 signaling. Our study characterizes the first GEMM that develops C-SCLC, a poorly-studied human cancer and implicates a role for NRF2 activation in SCLC development.

Development of an in vitro carcinogenesis model of human papillomavirus-induced cervical adenocarcinoma.

Cervical adenocarcinoma (ADC) is the second most common pathological subtype of cervical cancer after squamous cell carcinoma. It accounts for approximately 20% of cervical cancers, and the incidence has increased in the past few decades, particularly among young patients. The persistent infection of high‐risk human papillomavirus (HPV) is responsible for most cervical ADC. However, almost all available in vitro models are designed to study the carcinogenesis of cervical squamous cell carcinoma. To gain better insights into molecular background of ADC, we aimed to establish an in vitro carcinogenesis model of ADC. We previously reported the establishment of an in vitro model for cervical squamous cell carcinoma by introducing defined viral and cellular oncogenes, HPV16 E6 and E7, c‐MYC, and activated RAS to human cervical keratinocytes. In this study, the expression of potential lineage‐specifying factors and/or SMAD4 reduction was introduced in addition to the defined four oncogenes to direct carcinogenesis toward ADC. The cell properties associated with the cell lineage were analyzed in monolayer and organoid cultures and the tumors in mouse xenografts. In the cells expressing Forkhead box A2 (FOXA2), apparent changes in cell properties were observed, such as elevated expression of columnar cell markers and decreased expression of squamous cell markers. Strikingly, the histopathology of tumors expressing FOXA2 resembled cervical ADC, proposing that FOXA2 plays a vital role in dictating the histopathology of cervical cancers.

A Challenging and Rare Case of Metastatic Follicular Dendritic Cell Sarcoma Originating from a Tonsil

Abstract Introduction/Objective Follicular dendritic cell sarcoma (FDCS) is a rare malignant tumor of follicular dendritic cells. Most cases of FDCS are described in lymph nodes, but it can involve extra-nodal locations such as the tonsil. Methods/Case Report We report a case of a 55-year-old male with a 6-month history of a slow growing left neck mass. The patient had a poorly differentiated carcinoma of the left tonsil diagnosed based on morphologic features eight years ago, followed by chemoradiation, and subsequent left tonsillectomy without tumor identified. Imaging reported a 4.0 cm mass in the left neck level III lymph node location. Biopsy of the mass revealed a spindle cell neoplasm. It was difficult to reach a definitive diagnosis despite an extensive work-up. Review of the previous left tonsil biopsy showed a pleomorphic epithelioid cell proliferation. On the radical resection specimen of the left neck mass, a 4.5 cm, tan-gray, fleshy, necrotic mass was present. Microscopically, it demonstrated a neoplasm with spindle cell and epithelioid cell proliferation, with extensive necrosis. A wide panel of immunostains was performed; the tumor cells showed positivity for CD21, CD23, CD35, and focally weak positivity for cytokeratin OSCAR and Synaptophysin. Squamous cell markers were negative. These findings are consistent with FDCS. Further work-up on the original tonsil tumor displayed immunostaining profile of FDCS. This case was consulted with the National Institute of Health (NIH) for confirmation of the diagnosis. Results (if a Case Study enter NA) NA Conclusion Morphologically, FDCS can present with various histologic patterns, which can lead to diagnostic pitfalls, and common confusion with poorly differentiated carcinoma or soft tissue tumors, especially in needle biopsies. Generally, patients present with a prolonged clinical course, with a 50% and 25% chance of recurrence and metastasis respectively, hence the awareness and accurate diagnosis of this entity is important in biopsies of lymph nodes or of extranodal locations such as a tonsil.

GATA4 blocks squamous epithelial cell gene expression in human esophageal squamous cells

GATA4 promotes columnar epithelial cell fate during gastric development. When ectopically expressed in the developing mouse forestomach, the tissue emerges as columnar-like rather than stratified squamous with gene expression changes that parallel those observed in the pre-malignant squamous to columnar metaplasia known as Barrett’s esophagus (BE). GATA4 mRNA up-regulation and gene amplification occur in BE and its associated cancer, esophageal adenocarcinoma (EAC), and GATA4 gene amplification correlates with poor patient outcomes. Here, we explored the effect of ectopic expression of GATA4 in mature human esophageal squamous epithelial cells. We found that GATA4 expression in esophageal squamous epithelial cells compromised squamous cell marker gene expression and up-regulated expression of the canonical columnar cell cytokeratin KRT8. We observed GATA4 occupancy in the p63, KRT5, and KRT15 promoters, suggesting that GATA4 directly represses expression of squamous epithelial cell marker genes. Finally, we verified GATA4 protein expression in BE and EAC and found that exposure of esophageal squamous epithelial cells to acid and bile, known BE risk factors, induced GATA4 mRNA expression. We conclude that GATA4 suppresses expression of genes marking the stratified squamous epithelial cell lineage and that this repressive action by GATA4 may have implications in BE and EAC.

P63 Deficiency and CDX2 Overexpression Lead to Barrett's-Like Metaplasia in Mouse Esophageal Epithelium.

The cellular origin and molecular mechanisms of Barrett's esophagus (BE) are still controversial. Trans-differentiation is a mechanism characterized by activation of the intestinal differentiation program and inactivation of the squamous differentiation program. Renal capsule grafting (RCG) was used to elucidate whether CDX2 overexpression on the basis of P63 deficiency in the esophageal epithelium may generate intestinal metaplasia. P63-/-;Villin-Cdx2 embryos were generated by crossing P63+/- mice with Villin-Cdx2 mice. E18.5 esophagus was xenografted in a renal capsule grafting (RCG) model. At 1, 2, or 4weeks after RCG, the mouse esophagus was immunostained for a proliferation marker (BrdU), squamous transcription factors (SOX2, PAX9), squamous differentiation markers (CK5, CK4, and CK1), intestinal transcription factors (CDX1, HNF1α, HNF4α, GATA4, and GATA6), intestinal columnar epithelial cell markers (A33, CK8), goblet cell marker (MUC2, TFF3), Paneth cell markers (LYZ and SOX9), enteroendocrine cell marker (CHA), and Tuft cell marker (DCAMKL1). The P63-/-;Villin-Cdx2 RCG esophagus was lined with proliferating PAS/AB+ cuboidal cells and formed an intestinal crypt-like structure. The goblet cell markers (TFF3 and MUC2) and intestinal transcription factors (CDX1, HNF1α, HNF4α, GATA4, and GATA6) were expressed although no typical morphology of goblet cells was observed. Other intestinal cell markers including enteroendocrine cell marker (CHA), Paneth cell markers (LYZ and Sox9), and intestinal secretory cell marker (UEA/WGA) were also expressed in the P63-/-;Villin-Cdx2 RCG esophagus. Squamous cell markers (PAX9 and SOX2) were also expressed, suggesting a transitional phenotype. CDX2 overexpression on the basis of P63 deficiency in esophageal epithelial cells induces Barrett's-like metaplasia in vivo. Additional factors may be needed to drive this transitional phenotype into full-blown BE.

Relationship between morular metaplasia and squamous differentiation in endometrial carcinoma

Morular metaplasia (MM) is a peculiar type of metaplastic change commonly observed in endometrial lesions, which is defined by the absence of overt squamous features and a characteristic immunophenotype. The nature of MM and its relationship with conventional squamous differentiation (SD) is still undefined.Here, we present a morphological and immunophenotypical study of cases with mixed MM/SD and conventional SD, providing new insights on this field.Twenty cases of endometrioid carcinoma (10 with mixed MM and SD and 10 with conventional SD) were assessed by immunohistochemistry for β-catenin, CD10, CDX2, ki67, p63, p40, estrogen receptor (ER), progesterone receptor (PR) and cytokeratins (CK) 5/6, 7, 8/18 and 19.In mixed MM/SD cases, SD was mostly located within the MM areas; several degrees of SD development were observed within MM, from cells with larger cytoplasm and prominent membrane, to overt SD with morular shape and ghost cell keratinization. In the MM→SD transition, there was progressive loss of nuclear β-catenin, CD10, CDX2 and CK8/18 expression, increase of CK5/6 and CK7 expression, and stable CK19 positivity. ER, PR and ki67/MIB1 expression was low-to-negative in both MM and SD. The squamous cell markers p63 and p40 were mostly expressed at the interfaces between MM and SD. Conventional SD cases showed direct transition from glandular epithelium to SD with a surface growth and no ghost cell keratinization; immunohistochemistry showed strong positivity for ER, PR and all CKs, basal positivity for p63, p40 and ki67/MIB1, negativity for nuclear β-catenin, CD10 and CDX2.In conclusion, MM appears as the precursor of a peculiar form of SD, which differs morphologically and immunophenotypically from conventional SD. Defining MM based on the absence of overt squamous might not be meaningful. Further studies are necessary to clarify the nature of MM.

Human Lung Adenocarcinoma-Derived Organoid Models for Drug Screening

SummaryLung cancer is an extremely heterogeneous disease, and its treatment remains one of the most challenging tasks in medicine. Few existing laboratory lung cancer models can faithfully recapitulate the diversity of the disease and predict therapy response. Here, we establish 12 patient-derived organoids from the most common lung cancer subtype, lung adenocarcinoma (LADC). Extensive gene and histopathology profiling show that the tumor organoids retain the histological architectures, genomic landscapes, and gene expression profiles of their parental tumors. Patient-derived lung cancer organoids are amenable for biomarker identification and high-throughput drug screening in vitro. This study should enable the generation of patient-derived lung cancer organoid lines, which can be used to further the understanding of lung cancer pathophysiology and to assess drug response in personalized medicine.

The role of the immunohistochemical marker p40 in the differential diagnosis of adenocarcinoma and nonkeratinizing squamous cell cancer of the lung

Lung cancer is one of the main causes of cancer death. It is a heterogeneous group of malignant neoplasms, the treatment tactics for which directly depends on tumor morphology and genetic characteristics. However, the pathomorphological differential diagnosis of adenocarcinoma and squamous cell cancer of the lung is difficult in some cases and an immunohistochemical (IHC) study is needed to verify these tumors; moreover, the IHC panel should include both squamous cell and pneumocyte markers. Fifty surgical and biopsy specimens underwent morphological and IHC studies using antibodies against p40, p63, CK5/6, CK7, and TTF1. In this investigation, p40 showed a higher specificity than another squamous cell differentiation marker, such as p63; this confirms the data that it is advisable to use the marker p40 to verify squamous cell lung carcinoma. If there is a small amount of material for an IHC study in the differential diagnosis of adenocarcinoma from squamous cell cancer of the lung, the optimal solution is to limit the IHC panel to two markers, such as p40 and TTF1.

Abstract C41: Establishment of a novel mouse model of pancreatic squamous carcinoma

Abstract Pancreatic cancer is a lethal malignancy with the highest mortality rate among all cancers and a 5-year survival rate of 9% in the US. Among all subtypes of pancreatic cancers, the molecular mechanisms underlying the development of squamous carcinomas are not well understood. While pure squamous carcinoma makes up only 0.05-5% of all pancreatic cancers, it is very aggressive and leads to the worst prognosis among all pancreatic cancers. However, animal models to study the initiation and progression of pancreatic squamous carcinoma are lacking. Genetic studies have recently revealed the molecular signature of pancreatic cancers and identified the transcription factor p63 as a candidate that contributes to the development of pancreatic carcinomas. In one study (Bailey et al., Nature 2016;47-52), upregulation of the p63-mediated transcriptional network was reported. Another genome-wide analysis has identified a SNP in the p63 gene as a risk factor for the development of pancreatic cancers (Childs et al., Nat Genet 2015;911-6). Furthermore, it has been shown that expression of TAp63, an isoform of p63 with a tumor suppressor function, is frequently suppressed in pancreatic cancers (Bailey et al., Nature 2016;47-52). While p63 is rarely mutated in human cancers, ΔNp63α, the predominant isoform of p63 in epithelia, is overexpressed in a variety of human cancers of squamous cell origin. Notably, although p63 proteins are not expressed in normal pancreatic cells, they are expressed at high levels in areas of squamous differentiation of pancreatic cancers (Basturk et al., Modern Pathol 2005;1193-8). We hypothesize that aberrant expression of ΔNp63α in the pancreatic epithelia drives the tumorigenesis of pancreatic squamous carcinomas. To test this hypothesis, we have created transgenic (Tg) mice conditionally expressing ectopic ΔNp63α upon crossing with tissue/cell type-specific Cre-Tg mice in the presence of the K-rasG12D mutation (Hingorani et al., Cancer Cell 2003;437-50), a pancreatic cancer-promoting factor. Our data show that Pdx1Cre:KrasG12D:ΔNp63α-Tg mice develop pancreatic squamous carcinoma as determined by the cellular morphology and the shift of the expression of cytokeratin 8 (K8), a pan-pancreatic epithelial cell marker, into K5, a squamous epithelial cell marker. Interestingly, the absence of the K-ras mutation did not lead to the development of pancreatic tumors, indicating that de novo expression of ΔNp63α alone is not sufficient for the generation of pancreatic squamous carcinomas. None of the mice in our control cohort of the Pdx1Cre:KrasG12D:p53+/- genotype (Bardeesy et al., PNAS 2006;5947-52) developed pancreatic squamous carcinomas or showed p63 expression, emphasizing the functional differences between the two p53 family members. We aim to further characterize our novel animal model and determine the molecular mechanisms by which p63 contributes to the squamous pathogenesis of pancreatic cancer. Citation Format: Filipa Pinto, Tachira Pichardo, Adrien Leu, Makoto Senoo. Establishment of a novel mouse model of pancreatic squamous carcinoma [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2019 Sept 6-9; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2019;79(24 Suppl):Abstract nr C41.

Clinicopathological analysis of cervical basaloid squamous cell carcinoma

Objective: To investigate the clinical and histopathological features of cervical basal squamous cell carcinoma (BSCC). Methods: A retrospective analysis of 10 cases of cervical BSCC was carried out. The clinical data and all the pathological sections were reviewed, the related immunohistochemical results were statistically analyzed, the clinicopathological features were analyzed, and then followed the prognosis. Results: (1) Clinical features: the median onset age of BSCC in cervix was 51 years old (ranged 35-69 years old), 5 of them were postmenopausal women. Vaginal bleeding was often seen in clinic (7 cases). Of the 10 cervical BSCC patients, 5 tested HPV types. All of them were HPV positive, including 2 cases of HPV 16 positive and 1 case of high-risk HPV positive. At the time of colposcopy, 3 cases showed exogenous nodular mass, 3 cases showed endogenous infiltrating mass, and 4 cases had unclear type of mass.(2)Treatment: of the 10 patients, 8 underwent hysterectomy+bilateral adnexal excision+pelvic lymphadenectomy, of which 6 underwent radiotherapy or chemotherapy after operation.Radiotherapy and chemotherapy were performed only in 2 cases. (3) Pathological features: histologically, the tumor cells were nests and stripe like growth, which were composed of basal like tumor cells. The cells had obvious heteromorphosis, less cytoplasm, deep dyed nuclei and common nuclear mitosis, and there were often palisade like structures around the cell nests, and some cells in the center of the cell nests were found to have acne like necrosis. It could be mixed with normal squamous cell carcinoma and squamous epithelial lesion. Among the 10 patients, 6 had immunohistochemical results. BSCC mainly expressed p16 and squamous cell markers such as p63, cytokeratin (CK) 5/6 and p40 protein, the positive expression rates were 3/3, 3/3, 2/2 and 3/3, respectively. A few expressed CK7 protein, and the positive expression rate was 1/3. (4) Prognosis: follow-up time ranged from 1 week to 64 months, and 2 cases were lost to follow-up. Among the 8 follow-up patients, 3 had iliac bone, lung or skin metastasis, and 5 had no recurrence or metastasis during the follow-up period. Conclusions: BSCC of cervix is a rare malignant tumor of cervix associated with high-risk HPV infection, p16 is more positive. The treatment is similar to that of normal cervical squamous cell carcinoma. Surgical resection and radiotherapy and chemotherapy are the most effective methods according to the clinical stage. At present, the disease is considered to be highly aggressive and the poor prognosis.

Co-localisation of Glandular and Squamous Cell Markers in Non-small Cell Lung Cancer.

Accurate classification of lung carcinomas is crucial for selecting appropriate and adequate chemotherapy treatment. In this study, glandular (adenocarcinoma), and squamous cell differentiation were examined in non-small cell lung carcinoma (NSCLC) without obvious light-microscopic signs of squamous and glandular differentiation. All lung tumours diagnosed as NSCLC (n=61), without obvious squamous or glandular features, were obtained by bronchial biopsy or core biopsy supported by computed tomography. They were diagnosed during 1996-2009, at the Department of Pathology, Gävle Hospital, Sweden. The tumours were examined immunohistochemically with antibodies against CK5/6, p63 (squamous cell markers) and carcinoembryonic antigen (CEA) (adenocarcinoma cell marker). Double immunostaining (p63/CEA) was also performed on individual tumours. The tumours originated from 36 males and 25 females, aged 54-83 years. Pure squamous cell differentiation (CK5/6 positive only) occurred in 34.4% (n=21) tumours and pure adenocarcinoma cell differentiation (CEA positive only) was present in 14.9% (n=9). Tumours with both squamous and adenocarcinoma features (CK5/6 and CEA positive) were most prevalent (47.5%, n=29). Two tumours (3.3%) were negative with both stains (and also synaptophysin negative). Double immunostaining (p63/CEA) revealed that squamous and adenocarcinoma markers were co-localised in cells in certain tumours. Co-localisation of squamous and adenocarcinoma markers in the same tumour cell suggests that additional analyses for novel biomarkers of specific lung cancer types may subsequently lead to a refined treatment choice for patients with the goal of improving clinical outcomes.

Human Conjunctival Epithelial Sheets Grown on Poly(Lactic-Co-Glycolic) Acid Membranes and Cocultured With Human Tenon's Fibroblasts for Corneal Repair.

We determine the feasibility of human conjunctival epithelial cells (hCjECs) on poly(lactic-co-glycolic) acid (PLGA) membranes for corneal epithelium regeneration. hCjECs on PLGA or polyester (PET) membranes with or without coculture of human Tenon's fibroblasts (hTFs) were compared in vitro, and to determine whether epithelial sheets grown on PLGA membranes can repair injured rabbit corneal epithelium by transplantation for 2 weeks in vivo. Primary hCjECs were cultured on PLGA or the original PET membrane-based transwell inserts with or without coculture of hTFs on the floor of the culture plate. Cell behaviors, such as proliferation and differentiation, were compared. For in vivo assessment, the corneas of rabbits were burned, and PLGA-based epithelial sheets then were transplanted for 2 weeks before histologic staining was conducted and analyzed to determine the effectiveness of the repair. Primary human epithelial cells on the PLGA membrane showed an increased proliferation when cocultured with fibroblasts, which was confirmed by CCK-8 analysis, and upregulation of Ki67, with the expression of the epithelial marker CK19. The stratified squamous cell marker MUC1 and conjunctival cell marker MUC5AC also were expressed in the epithelial sheet. The epithelial defect in the burned corneas was decreased in the PLGA-based epithelial sheet treatment group (6.1% ± 1.6% of the area) compared to that in the no-treatment group (30.5% ± 6.3%) 2 weeks postoperatively. We developed a coculture system using a human feeder cell layer and PLGA membrane-based transwell inserts to create human conjunctival epithelial sheets. This system represents a promising strategy to regenerate corneal epithelium by transplantation.

MUC4 immunohistochemistry is useful in distinguishing epithelioid mesothelioma from adenocarcinoma and squamous cell carcinoma of the lung

The differential diagnosis of epithelioid mesothelioma from lung adenocarcinoma and squamous cell carcinoma requires the positive and negative immunohistochemical markers of mesothelioma. The IMIG guideline has suggested the use of Calretinin, D2–40, WT1, and CK5/6 as mesothelial markers, TTF-1, Napsin-A, Claudin 4, CEA as lung adenocarcinoma markers p40, p63, CK5/6, MOC-31 as squamous cell markers. However, use of other immunohistochemical markers is still necessary. We evaluated 65 epithelioid mesotheliomas, 60 adenocarcinomas, and 57 squamous cell carcinomas of the lung for MUC4 expression by immunohistochemistry and compared with the previously known immunohistochemical markers. MUC4 expression was not found in any of 65 cases of epithelioid mesothelioma. In contrast, MUC4 expression was observed in 50/60(83.3%) cases of lung adenocarcinoma and 50/56(89.3%) cases of lung squamous cell carcinoma. The negative MUC4 expression showed 100% sensitivity, 86.2% specificity and accuracy rate of 91.2% to differentiate epithelioid mesothelioma from lung carcinoma. The sensitivity, specificity, and accuracy of MUC4 are comparable to that of previously known markers of lung adenocarcinoma and squamous cell carcinoma, namely CEA, Claudin 4 and better than that of MOC-31. In conclusion, MUC4 immunohistochemistry is useful for differentiation of epithelioid mesothelioma from lung carcinoma, either adenocarcinoma or squamous cell carcinoma.

Evolving concepts in lung cancer pathology and its impact on thoracic oncology practice

Lung cancer is the commonest cause of death worldwide but unfortunately, most patients present in an advanced stage of the disease. The classification of lung cancer has evolved since the first WHO publication in 1981, and the present edition was published in March 2015. A major change in 2015 was the introduction of the new terms adenocarcinoma in situ and minimally invasive adenocarcinoma to describe early adenocarcinoma of lung and abolition of the previous term bronchioloalveolar carcinoma. Tumors with micropapillary pattern and those showing spread through alveolar spaces have significant clinical implications with an increased propensity for recurrence. Tissue specimens require proper fixation in 10% buffered formalin which is an essential but an often neglected basic step; proper fixation is a prerequisite for good immunohistochemistry (IHC) and molecular test outcomes. Needle core biopsies should be handled judiciously to ensure that sufficient material is prioritized for molecular studies which are needed to guide personalized treatment. The WHO 2015 classification recommends the use of a single squamous cell marker (p40, or CK5/6) and a single adenocarcinoma marker (TTF1, or napsin) to distinguish squamous cell carcinoma and adenocarcinoma in difficult biopsies. The non-committal designation of non-small cell lung carcinoma (NSCLC) is discouraged. The exciting ongoing research findings on molecular biology of lung cancer necessitate constant expansion of laboratory test menu. Testing and treating lung cancer patients with epidermal growth factor (EGFR) mutation and anaplastic lymphoma kinase (ALK) gene fusion is now a standard of care, and ROS1 has been approved recently. The updated guidelines from the College of American Pathologists (CAP) and approval notifications from the Federal Drug Authority (FDA) are invaluable to justify initiation of new tests by pathology laboratories. Recently, FDA has approved testing for programmed death ligand (PDL1) with 22C3 antibody by IHC and EGFR testing on plasma by a non-invasive liquid biopsy test approach. To conclude, a comprehensive pathology report is vital for staging, comparing outcomes, and developing better strategies for patient care in the future.