CDX2 Positivity Research Articles

Mixed adenoma-neuroendocrine tumor of the stomach: analysis of nine cases with literature review.

Mixed adenoma-neuroendocrine tumor (MANET) comprises adenoma and well-differentiated neuroendocrine tumor (NET) components. Given the limited information on this due to its rarity, we aimed to clarify the clinicopathologic features and optimal management of gastric MANETs in a case series and literature review. Nine patients with gastric MANETs, including eight male and one female patient (mean age, 72years), were identified from the institutional pathology archive. Endoscopically, the tumors appeared as flat elevated lesions with sizes ranging from 0.8 to 4.4cm. One patient had familial adenomatous polyposis, and no patient had autoimmune gastritis. All MANETs developed in the gastric body mucosa exhibiting chronic metaplastic atrophic gastritis. The glandular components were intestinal-type low-grade adenoma, and focal high-grade dysplasia was also recognized in three cases. The NET component was in middle/deep lamina propria in six cases and confined to deep lamina propria in the remaining three cases. Minimal cytologic atypia was found in the NET component, with no recognizable mitosis and a Ki-67 labeling index of < 2%. The NET component mostly showed diffuse positivity for serotonin and CDX2, suggesting that it consists of enterochromaffin cells. Diffuse p53 immunostaining was observed only in the high-grade adenomatous component of one case. No recurrence was observed during the follow-up period of 2-94months. Correct distinction between the NET and poorly differentiated carcinoma components is crucial to prevent overtreatment of gastric MANETs. Considering its indolent nature, endoscopic resection is the primary recommendation for gastric MANETs as well as for pure adenomas.

Endoscopic Diagnosis of Epithelial Subtypes of Superficial Non-Ampullary Duodenal Epithelial Tumors using Magnifying Narrow-Band Imaging

Introduction: Superficial non-ampullary duodenal epithelial tumors (SNADETs) include low-grade adenoma (LGA) and high-grade adenoma or carcinoma (HGA/Ca) and are classified into two different epithelial subtypes, gastric-type (G-type) and intestinal-type (I-type). We attempted to distinguish them by endoscopic characteristics including magnifying endoscopy with narrow-band imaging (M-NBI). Methods: Various endoscopic and M-NBI findings of 286 SNADETs were retrospectively reviewed and compared between G- and I-types and histological grades. M-NBI findings were divided into four patterns based on the following vascular patterns; absent, network, intrastructural vascular (ISV), and unclassified. Lesions displaying a single pattern were classified as mono-pattern and those displaying multiple patterns as mixed-pattern. Lesions showing CDX2 positivity were categorized as I-types and those showing MUC5AC or MUC6 positivity were categorized as G-types based on immunohistochemistry. Results: Among 286 lesions, 23 (8%) were G-type and 243 (85%) were I-type. More G-type lesions were located oral to papilla (91.3 vs. 45.6%, p < 0.001), and had protruding morphology compared to those of I-types (65.2 vs. 14.4%, p < 0.001). The major M-NBI pattern was ISV in G-type (78.2 vs. 26.3%, p < 0.001), and absent for I-type (0 vs. 34.5%, p = 0.003). Three endoscopic characteristics; location oral to papilla, protruding morphology, and major M-NBI pattern (ISV) were independent predictors for G-type. Mixed-pattern was more common in HGA/Ca than LGA for I-type (77.0 vs. 58.8%, p = 0.01); however, there was no difference for those in G-type. Conclusion: Endoscopic findings including M-NBI are useful to differentiate epithelial subtypes.

MUCINOUS CYSTIC TUMOR OF LOW MALIGNANT POTENTIAL THOUGHT TO BE OF URACHAL ORIGIN: A CASE REPORT

Mucinous cystic tumor of low malignant potential (MCTLMP) is a very rare disease.The patient was a 50-year-old man. Contrast-enhanced computed tomography and magnetic resonance imaging showed a multiocular cystic lesion on the top of the bladder. We performed surgery to remove the tumor for definitive diagnosis. Intraoperative rapid pathological diagnosis of the cyst wall showed no malignant findings, so we performed combined resection of the peritoneum and part of the bladder wall.Based on imaging findings, tumor location, and pathological and immunostaining findings (CK20 and CDX2 positivity; β-catenin negativity), the patient was diagnosed with MCTLMP thought to be of urachal origin. After the operation, recurrence was not observed.

Mucin-Phenotype and Expression of the Protein V-Set and Immunoglobulin Domain Containing 1 (VSIG1): New Insights into Gastric Carcinogenesis.

In gastric cancer (GC), intestinal metaplasia (IM) is a common precursor lesion, but its relationship to the MUC2/MUC5AC/CDX2 axis is not completely understood. Although V-set and immunoglobulin domain containing 1 (VSIG1) is supposed to be a specific marker for gastric mucosa and GC, respectively, no data about its relationship with IM or mucin phenotype have been published. The aim of our study was to explore the possible linkage between IM and these four molecules. The clinicopathological features of 60 randomly selected GCs were examined in association with VSIG1, MUC2, MUC5AC and CDX2. Two online database platforms were also used to establish the transcription factors (TFs) network involved in MUC2/MUC5AC/CDX2 cascade. IM was more frequently encountered in females (11/16 cases) and in patients below 60 years old (10/16 cases). Poorly differentiated (G3) carcinomas tended to show a loss of CDX2 (27/33 cases) but not of MUC2 and MUC5AC. MUC5AC and CDX2 were lost in parallel with the depth of invasion of the pT4 stage (28/35 and 29/35 cases), while an advanced Dukes-MAC-like stage was only correlated with CDX2 and VSIG1 loss (20/37 and 30/37 cases). VSIG1 was directly correlated with MUC5AC (p = 0.04) as an indicator of gastric phenotype. MUC2-negative cases showed a propensity towards lymphatic invasion (37/40 cases) and distant metastases, while CDX2-negative cases tended to associate with hematogenous dissemination (30/40 cases). Regarding the molecular network, only 3 of the 19 TFs involved in this carcinogenic cascade (SP1, RELA, NFKB1) interacted with all targeted genes. In GC, VSIG1 can be considered an indicator of gastric phenotype carcinomas, where carcinogenesis is mainly driven by MUC5AC. Although infrequently encountered in GC, CDX2 positivity might indicate a locally advanced stage and risk for vascular invasion, especially in tumors developed against the background of IM. The loss of VSIG1 indicates a risk for lymph node metastases.

Mucinous adenocarcinoma of the prostatic urethra after brachytherapy for prostatic adenocarcinoma: a case series

Mucinous adenocarcinoma of the urethra is extremely rare, even more so in a setting of postradiation therapy, with only 3 cases reported up to date including the first case published by our group in 2011. In the present study, we included the long-term follow-up on our previously reported case and report 3 additional cases. This is the first case series to date of this rare disease entity. The aim of this study is to review the clinicopathologic features of mucinous adenocarcinoma of the prostatic urethra in patients after receiving brachytherapy for prostatic adenocarcinoma. We identified 4 patients with a mean age of 72 years, and a mean interval of 14.8 years from brachytherapy for prostate carcinoma (grade group 1). Patients presented with hematuria or urinary retention. A colonoscopy was performed in three-fourth of patients and was within normal limits. Three patients underwent cystoprostatectomy and 1 had a transurethral resection of the prostate. On gross examination, only tumor formed a 3.5cm tan-gray, ulcerated, friable, and necrotic mass and 2 displayed either irregular red granular or thickened areas within the prostatic urethra. Abundant extracellular mucin pools dissecting the prostatic stroma were present in all tumors, with clusters of tumor cells floating in the mucin. The mucin pools were lined by pleomorphic pseudostratified columnar mucinous epithelium. Tumors were diffusely positive for CK20, CDX2 (4/4), and AMACR (2/2); they focally expressed CK7 (2/4), and lacked nuclear β-catenin expression (3/3). PSA, PSAP, NKX3.1, p63, and GATA3 were negative in the tumors tested. Among the 3 patients who underwent radical surgery, 2 had stage 2 tumors (confined to the prostatic urethra and prostate), and 1 had a stage 3 tumor, with seminal vesicle involvement. All 4 patients were alive without disease with a mean follow-up of 4.9 years. In conclusion, brachytherapy-associated mucinous adenocarcinoma of the prostatic urethra displays intestinal-type features as its non-radiation-related counterpart. It appears to lack a villous adenoma component, displays a different immunohistochemical profile with diffuse CK20 and CDX2 positivity, and is associated with lower stage and less aggressive behavior.

CDX2 expression in primary skin tumors—case series and review of the literature

CDX2 expression characterizes tumors of gastrointestinal origin, including those of intestinal-type differentiation. In dermatopathology, CDX2 expression is reported in 4 settings: cutaneous metastases from carcinomas of intestinal origin or differentiation, extramammary Paget's disease associated with an underlying colorectal or urothelial tumor, pilomatricomas and pilomatrical carcinomas, and rare primary cutaneous (adeno)squamous carcinomas with intestinal immunophenotype. Over 4 years (10/2017-10/2021), 252 dermatopathology cases with CDX2 immunostain were reviewed, revealing 46 cases with confirmed positive staining. Among them, 11 cases confirmed as primary nonintestinal type cutaneous carcinoma with definitively positive CDX2 nuclear staining were further studied. All cases demonstrated basaloid morphology with atypia, variable necrosis, and brisk mitotic activity. Cases 1-5 had heterogeneous features that cannot be further classified, including 2 cases with neuroendocrine or pseudoglandular/pseudopapillary features, and 1 case with human papillomavirus high-risk E6/E7 ISH positivity. In cases 6 through 11, the diagnosis of pilomatrical carcinoma was supported morphologically. This study substantiates the association of CDX2 with pilomatrical carcinoma. In addition, CDX2 positivity was observed in a subset of basaloid cutaneous carcinomas of ambiguous classification. However, this finding also raises a diagnostic pitfall in clinical diagnostic specificity of the CDX2 immunostain in skin cancers, which can be observed in rare while heterogeneous subsets of primary cutaneous carcinomas with primitive cytomorphology.

Multifocal diffuse large cell neuroendocrine carcinoma of the colon

Large cell neuroendocrine carcinomas (LCNEC) of the colon are an extremely rare and aggressive type of colorectal cancer. While multifocality is more frequently seen in small intestine NECs, no cases of multifocal NEC of the colon have been reported before. A 69-year-old male patient presented with abdominal pain. Colonoscopy revealed a necrotic-polypoid mass in the sigmoid colon and the biopsy result was reported as malignant epithelial tumor. Laparoscopic anterior resection was performed with the preliminary diagnosis of colon adenocarcinoma. Histopathological examination revealed three polypoid tumors, the largest of which was 4 cm, in the sigmoid colon. Immunohistochemical examination showed positivity for synaptophysin, chromogranin, and CDX2. High Ki67 proliferation index, high mitosis, and widespread p53 expression were observed in all tumors. With these findings, a diagnosis of multifocal large cell NEC was made. To the best of our knowledge, this is the first report describing a case of multifocal large cell NEC of the colon. LCNECs of the colon are very aggressive. Here, we report for the first time a case of multifocal LCNEC. In a short period of 1 month after the surgery, new widespread metastases were detected in the liver. Therefore, these tumors should be followed more closely than usual for early treatment.

CDX2andSATB2positivity in pilomatrix carcinoma: Avoiding an erroneous diagnosis of cutaneous metastasis of gastrointestinal origin

An 80-year-old female presented with a slowly growing 2-cm nodule on her shoulder over a 1-year period. Histopathologic sections of a biopsy specimen showed a multinodular, dermal-based basaloid tumor with areas of clear-cell change, stromal induction, as well as significant cytologic atypia and atypical mitotic activity. An initial investigation revealed positive staining of CDX2, a well-known marker of tumors of gastrointestinal origin. The case was referred to our dermatopathology service for consultation to determine if the lesion was in keeping with a cutaneous metastasis. On receipt of the case, an extended immunohistochemical panel was performed including SATB2, which displayed a similar pattern of staining as seen with CDX2. Although pathologists are most familiar with CDX2 and SATB2 as markers of gastrointestinal origin, the recent dermatopathology literature highlights that primary adnexal lesions of the skin also display positivity for CDX2 and can exhibit SATB2 positivity. We share a case of pilomatrix carcinoma with positive expression of nuclear CDX2 and SATB2, adding to the recent literature to (a) increase recognition of this staining pattern in hair follicle tumors, and (b) discuss briefly the shared molecular underpinnings in the tumorigenesis of gastrointestinal tumors and tumors of hair follicle origin that help clarify this underrecognized immunohistochemical pattern.

Abstracts and Case Studies for the College of American Pathologists 2021 (CAP21) Annual Meeting

Abstracts and Case Studies for the College of American Pathologists 2021 (CAP21) Annual Meeting

Neuroendocrine tumor (NET) of the vagina in the light of WHO 2020 2-tiered grading system: clinicopathological report of the first described case.

Up to now, a vaginal well-differentiated neuroendocrine tumor (NET) has never been well described in the literature. A 2-cm vaginal nodule morphologically revealed a proliferation of mild to moderately atypical eosinophilic epithelioid cells, without tumor cell necrosis. Immunohistochemistry (IHC) showed positivity for CK (AE1/AE3), chromogranin A, and synaptophysin, focal positivity for CDX2, and negativity for PAX8 and TTF1. Metastatic origin was excluded by imaging and the morphological context with benign mucinous glands as present in the surgical resection specimen. Considering mitotic index and Mib1/Ki67 (8 mitoses/2 mm2; >20%), the case was diagnosed as vaginal NET G2 in the light of the WHO 2020 grading system for the gynecologic neuroendocrine neoplasms (NENs). Ranges of Mib1-Ki67 are not yet standardized. Currently, mitotic index and tumor cell necrosis were taken into consideration for the grading system. Gynecologic NENs still represent a diagnostic challenge. A clinico-radiologic workup and an appropriate diagnostic path ruling out the metastatic nature are mandatory to achieve the diagnosis.

Does endometrial morular metaplasia represent odontogenic differentiation?

The nature of endometrial morular metaplasia (MorM) is still unknown. The nuclear β-catenin accumulation and the not rare ghost cell keratinization suggest a similarity with hard keratin-producing odontogenic and hair matrix tumors rather than with squamous differentiation. We aimed to compare MorM to hard keratin-producing tumors. Forty-one hard keratin-producing tumors, including 26 hair matrix tumors (20 pilomatrixomas and 6 pilomatrix carcinomas) and 15 odontogenic tumors (adamantinomatous craniopharyngiomas), were compared to 15 endometrioid carcinomas with MorM with or without squamous/keratinizing features. Immunohistochemistry for β-catenin, CD10, CDX2, ki67, p63, CK5/6, CK7, CK8/18, CK19, and pan-hard keratin was performed; 10 cases of endometrioid carcinomas with conventional squamous differentiation were used as controls. In adamantinomatous craniopharyngiomas, the β-catenin-accumulating cell clusters (whorl-like structures) were morphologically similar to MorM (round syncytial aggregates of bland cells with round-to-spindled nuclei and profuse cytoplasm), with overlapping squamous/keratinizing features (clear cells with prominent membrane, rounded squamous formations, ghost cells). Both MorM and whorl-like structures consistently showed positivity for CD10 and CDX2, with low ki67; cytokeratins pattern was also overlapping, although more variable. Hard keratin was focally/multifocally positive in 8 MorM cases and focally in one conventional squamous differentiation case. Hair matrix tumors showed no morphological or immunophenotypical overlap with MorM. MorM shows wide morphological and immunophenotypical overlap with the whorl-like structures of adamantinomatous craniopharyngiomas, which are analogous to enamel knots of tooth development. This suggests that MorM might be an aberrant mimic of odontogenic differentiation.

Comprehensive immunohistochemical analysis of the gastrointestinal and Müllerian phenotypes of 139 ovarian mucinous cystadenomas

Mucinous cystadenoma is one of the most common benign ovarian neoplasms. The immunophenotypes and histogenetic relationships of mucinous cystadenomas with a Müllerian-type epithelium have not been fully explored. We elucidated the direction of differentiation of the mucinous epithelium that constitutes mucinous cystadenomas. Special attention was paid to the existence of gastrointestinal (GI)-type mucinous epithelium, and its association with background Müllerian-type epithelium. Immunohistochemistry was performed in 139 cases of mucinous cystadenoma to evaluate the expression of Claudin-18 (CLDN18), a novel marker of gastric differentiation; CDX2, a marker of intestinal differentiation; and estrogen receptor (ER), a marker of Müllerian differentiation. We found that GI differentiation characterized by CLDN18 and/or CDX2 positivity was observed in mucinous epithelium of most mucinous cystadenomas (129/139 cases, 93%). In a subset of these cases, the tumor was composed of mucinous epithelium exhibiting an intermediate GI and Müllerian phenotype (CLDN18+/CDX2±/ER+). Of note, in 12 cases, a transition from background Müllerian-type epithelium to mucinous epithelium with GI differentiation was identified. A minor subset (6%) of mucinous cystadenomas was considered a pure Müllerian type because the epithelium exhibited a CLDN18-/CDX2-/ER+immunophenotype. In conclusion, mucinous cystadenomas consist of three major subtypes: GI, Müllerian, and intermediate types. Most mucinous cystadenomas are GI-type, and they should be considered a precursor of GI-type mucinous borderline tumors. The existence of intermediate-type mucinous cystadenomas, and areas of transition from Müllerian-type to GI-type epithelium suggest that GI-type mucinous epithelium can arise from Müllerian duct derivatives or surface epithelium exhibiting Müllerian metaplasia in the ovary.

CDX2 Expression in Primary and Metastatic Prostatic Adenocarcinoma: A Retrospective Study

Abstract Introduction/Objective CDX2 encodes a transcription factor expressed in the nuclei of intestinal epithelial cells. The CDX2 immunohistochemical stain has excellent diagnostic utility in the setting of carcinoma of unknown primary, especially in combination with cytokeratins 7 and 20. While the stain is fairly specific for intestinal origin, it is also expressed in tumors of other origins. Only rare case reports have described positivity for CDX2 in metastatic prostatic adenocarcinoma. Having experienced a diagnostic dilemma involving CDX2 positivity in metastatic prostate cancer, we decided to study the rate of positivity for CDX2 in primary and metastatic prostate carcinomas. A literature search revealed several immunoassay studies and case reports of CDX2 positivity in the primary and metastatic setting. Methods Following IRB approval, a search of the electronic medical records was performed to identify prostatic adenocarcinoma diagnoses on prostatectomy and metastatic specimens. Formalin-fixed, paraffin embedded blocks were obtained. Unstained slides were cut at 4µm and the staining protocol for CDX2 from Cell Marque™ was performed. 109 cases were stained, including 88 prostatectomy and 21 metastatic specimens. Results Of the 109 cases, 75 were negative for CDX2, including 19 of the 21 metastatic cases. Of the remaining 34 cases, 10 were strongly positive for CDX2, including two metastatic cases (clavicle and right iliac bone). The remaining 24 were identified as weakly positive (12 cases), focally positive (7 cases), weakly and focally positive (3 cases), or patchy positive (2 cases). Overall, 36.36% of prostatectomy specimens had tumors with some CDX2 positivity, compared to 9.52% of metastatic cases. The patient ages at diagnosis ranged from 44 to 84 years, with a median value of 59 years, and at metastasis ranged from 51 to 87 years, with a median age of 64. PSA ranged from 2.8 to 3564 at diagnosis (median 9) and undetectable to 2024 at metastasis (median 56). Conclusion CDX2 is often positive to some degree in both benign and malignant prostates, and can present a diagnostic pitfall in the case of metastasis. Hence, CDX2 positivity does not exclude the diagnosis of prostate cancer in the evaluation of unknown primary. In our study, the number of metastatic cases studied was relatively low. Future studies with more cases could better quantify the positive rate for CDX2 in metastatic prostate adenocarcinoma.

Gastric Adenocarcinoma with Enteroblastic Differentiation: A Rare Find

Abstract Casestudy: Gastric adenocarcinoma with enteroblastic differentiation (GAED), also called clear cell gastric carcinoma, is a subtype of alpha-fetoprotein (AFP) producing adenocarcinoma. GAED is not a well-documented malignancy. Due to rarity, it is often skipped from the list of gastric adenocarcinoma subtypes. We report a case of Gastric adenocarcinoma with enteroblastic differentiation in a 69-year-old male, who had an endoscopy that revealed an ulcerated, circumferential, malignant-appearing mass at the distal esophagus. The patient then underwent proximal gastrectomy with distal esophagectomy. Received was a portion of the proximal stomach and distal esophagus. On gross examination, a 2.6 cm ulcerated mass was present at the gastroesophageal junction with white, friable, and focally necrotic cut surface. H&amp;E stained slides demonstrated a malignant tumor composed of cuboidal to columnar neoplastic cells with clear cytoplasm and prominent nucleoli. The neoplastic cells were arranged in tubular, solid, and trabecular growth patterns. There were also areas of admixed conventional moderately differentiated adenocarcinoma with overlying glandular dysplasia and focal intestinal metaplasia. Immunohistochemical stains demonstrated tumor positivity for CDX2 (strong) and AFP (focal). Neuroendocrine markers were negative within the tumor. In Conclusion, GAED is a rare malignancy with distinctive clinicopathologic features and associated aggressive behavior. Morphology and immunohistochemical stains are helpful in making the diagnosis of this rare malignancy.

A CASE OF MUCIN-PRODUCING UROTHELIAL-TYPE ADENOCARCINOMA OF THE PROSTATE (MPUAP) WITH LONG-TERM SURVIVAL AFTER TOTAL CYSTECTOMY

Mucin-producing urothelial-type adenocarcinoma of the prostate (MPUAP) is a very rare disease. MPUAP has been reported to progress faster than the rate at which normal prostate cancer progresses. We report a case of MPUAP with long-term survival. The patient was a 65-year-old man. Computed tomography and magnetic resonance imaging showed a cystic lesion extending from the prostate to the urethra. We performed transrectal prostate biopsy and transurethral resection of the tumor, and the pathological diagnosis was adenocarcinoma. Subsequently, we performed total cystectomy, ureterostomy, and pelvic lymphadenectomy. Based on the pathological and immunostaining findings (prostate-specific antigen negativity, CDX-2 positivity, cytokeratin 20 positivity, 34β-E12 positivity), the patient was diagnosed with MPUAP. Four years after the surgery, recurrence or metastasis was not observed.

CDX-2 Expression in Esophageal Biopsies Without Goblet Cell Intestinal Metaplasia May Be Predictive of Barrett's Esophagus.

CDX-2 is a nuclear homeobox transcription factor not normally expressed in esophageal and gastric epithelia, reported to highlight intestinal metaplasia (IM) in the esophagus. Pathological absence of goblet cells at initial screening via hematoxylin and eosin (HE) and alcian blue (AB) staining results in patient exclusion from surveillance programs. This study aimed to determine whether non-goblet cell IM, as defined by CDX-2 positivity, can be considered to be a precursor to Barrett's esophagus (BE). This study received IRB approval (17,284). Patients with gastroesophageal reflux disease (n = 181) who underwent upper-gastrointestinal endoscopy with biopsies of the distal esophagus to rule out BE using HE/AB staining and CDX-2 immunostaining were followed for 3years. Initial and follow-up staining results were evaluated for age/sex. Differences between development of goblet cell IM in CDX-2-negative and CDX-2-positive groups were evaluated. A Kaplan-Meier curve showed that, out of the 134 patients initially positive for CDX-2, 25 (18.7%) had developed goblet cell IM after 2years and 106 (79.1%) after 3years. Conversely, of the 47 patients initially negative for CDX-2, 8 (17.9%) developed goblet cell IM after 24months and only 11 (23.8%) after 40 to 45months (P = .049; age-adjusted Cox proportional hazard regression model). In cases that are initially AB negative and CDX-2 positive, CDX-2 was demonstrated to have a potential prognostic utility for early detection of progression to BE. CDX-2 expression is significantly predictive for risk of goblet cell IM development 40 to 45months after initial biopsy.

Pancreatic Intraepithelial Neoplasia (PanIN) as a Morphologic Marker of Pancreatobiliary Type of Ampullary Carcinoma.

The classification of ampullary adenocarcinoma into intestinal and pancreatobiliary sub-types has been found to be important in predicting prognosis and determining therapeutic strategy. Due to considerable inter-observer variability in sub-typing based solely on morphology, higher frequency of poorly differentiated cancers and low incidence of the disease, the histomorphologic classification of ampullary adenocarcinoma remains one of the grey zones in surgical pathology. Pan-IN is a well recognized precursor to pancreatic adenocarcinoma. Three studies have shown concurrent Pan-IN in patients with ampullary carcinoma, but their association with the two sub-types has not yet been reported. Fourteen cases of surgical resection for ampullary adenocarcinoma were retrieved from the archives. The cases were classified into two groups based on the presence or absence of concomitant Pan-IN. All the cases were stained for CK7, CK 20, Villin and CDX 2 and were classified as intestinal or pancreatobiliary types based on the staining pattern. All the 10 cases with Pan-IN stained negative for CDX2 and were classified as pancreatobiliary type (p = 0.01). Of the cases without Pan-IN, 3 were classified as intestinal sub-type based on morphology and CDX2 positivity and 1 was classified as pancreatobiliary type. Concomitant Pan-IN was present in 91% of pancreatobiliary type of ampullary adenocarcinoma. The grade of Pan-IN did not influence the grade or stage of the adenocarcinoma (p > 0.05). The co-occurrence of Pan-IN in a high percentage of the pancreatobiliary sub-type and its complete absence in the intestinal sub-type may serve as a strong differentiator between the two sub-types.

422 Positive Association Between CDX2 and MUC2 Intestinal Factors and Dysplasia in Barrett’s Esophagus Utilizing WATS3D Tissue Sampling and Analysis

INTRODUCTION: During the pathogenesis of Barrett’s esophagus (BE), the background columnar epithelium often shows evidence of intestinal differentiation, such as early expression of intestinal specific transcription factors (CDX2) and late expression of mucin proteins (MUC2), prior to the development of goblet cells. The clinical significance of these markers is unknown. The aim of this study was to evaluate the association between the expression of CDX2 and MUC2, and the presence and grade of dysplasia in a large cohort of patients with endoscopic evidence of esophageal columnar mucosa using wide area transepithelial samples (WATS3D, CDx Diagnostics, Suffern, NY). METHODS: Over a 2-year period, we collected data from 129,158 consecutive patients with endoscopic evidence of esophageal salmon colored mucosa who were evaluated with WATS: 125,749 no dysplasia (ND), 2,012 crypt dysplasia (CD), 745 low grade dysplasia (LGD), and 652 high grade dysplasia/adenocarcinoma (HGD/EAC). CDX2 and MUC2 immunostaining was performed, and then their extent was graded semi-quantitatively (on a 4-point scale) in the background non-dysplastic, non-goblet epithelium, from all patients. The CDX2 and MUC2 results were then correlated statistically with the presence and grade of dysplasia. RESULTS: Table 1 summarizes the data according to dysplasia grade. Overall, 33.3% of cases were CDx2- MUC2-, 30.6% were CDx2+ MUC2-, and 36.1% were CDX2+ MUC2+. A significant (P &lt; 0.0001) increase in CDX2+ MUC2+ staining occurred in dysplasia cases (97.0%) compared to non- dysplasia cases (34.5%). Upon regression analysis, there was a highly significant (P &lt; 0.0001) association between both the presence and grade of CDX2 and MUC2 staining and dysplasia, that increased progressively from CD to LGD to HGD/EAC. CDX2+ MUC2+ was present, uniformly, in more than 94% of all dysplasia categories. In a sub-analysis of either CDX2 or MUC2 staining in ND vs. HGD/EAC cases only, there was a significant increase (P &lt; 0.0001) in the grade of CDX2, and in the grade of MUC2, staining, such that 3+ or 4+ CDX2 or MUC2 staining was noted in 8.8% and 9.1% of ND cases, respectively, compared to 54% and 41%, respectively, in HGD/EAC. CONCLUSION: CDX2 and/or MUC2 positivity is a highly significant risk factor for dysplasia/EAC in patients with endoscopic evidence of esophageal columnar mucosa. CDX2/MUC2 immunostaining may represent a more effective method of confirming Barrett’s esophagus, and the risk for dysplasia/cancer, than the identification of goblet cells.

638P - Development of a living organoid biobank derived from colorectal cancer patients: Towards personalized medicine

BackgroundOrganoids are 3D in vitroprimary culture of great interest for translational research representing an efficient and reproducible cancer model. The aim of this project is to generate a biobank of colorectal cancer (CRC) patients derived organoids (PDOs) that could be used to analyze molecular characteristics and to test different treatments as well as to study the underlying molecular causes of cancer and treatment resistance. MethodsPrimary or metastatic CRC tissues have been obtained from patients who underwent surgery. Tissue has been washed and incubated with antibiotics. After mechanical and enzymatic digestion, free cells have been seeded in Matrigel with proper medium. Development of organoids has been observed the day after seeding. Organoids have been passaged, expanded and stored in liquid nitrogen to constitute a biobank. For morphological characterization, after reaching an appropriate volume, organoids have been fixed in 4% paraformaldehyde, stained for hematoxylin and eosin (H&E) and immunohistochemistry (IHC) for ki67, CDX2, CK20, MUC2/5 was performed. Immunofluorescence (IF) for DAPI, Lgr5 and CDH1 has been performed.For genomic characterization, DNA has been extracted with phenol-chlorophorm and sequenced with an internal customized panel. A comparison statistical test with matched tissue has been performed. ResultsThe success rate in CRC-PDOs establishment is around 80%. PDOs staining with H&E shows a morphology comparable to the original tissue. IHC shows ki67 staining, nuclear positivity for CDX2, cytoplasmic CK20 and MUC2/5. IF evidences the positivity for the intestinal stem cells marker Lgr5 and CDH1 thus confirms that PDOs faithfully recapitulate original tissue morphology and cell composition.Between 80 and 120ng of genomic DNA has been sequenced. Spectrum of PDOs mutations and polimorphisms displays a good concordance with that of matched patients with an R of linear concordance of 0.9. ConclusionsWe have developed a robust protocol for efficient development of CRC PDOs. Organoids recapitulate morphological and genomic features of the original patient. They work as a solid in vitromodel, suitable for functional studies and drug screening, helping in promoting precision medicine. Legal entity responsible for the studyThe authors. FundingGrants from the Instituto de Salud Carlos III (PI15/02180 to AC and PI18/01508 to TF). FP is supported by the ESMO 2018 fellowship programme. VG was supported by the ESMO 2014 fellowship programme and by Rio Ortega contract CM18/00241 from the Carlos III Health Institute; TF is supported by Joan Rodes contract 17/00026 from the Carlos III Health Institute. NT was supported by Rio Ortega contract CM15/00246 from the Carlos III Health Institute; DR was supported by Joan Rodes contract 16/00040 from the Carlos III Health Institute. MFGB is supported by a Santiago Grisolia fellowship. DisclosureA. Cervantes: Advisory / Consultancy, Speaker Bureau / Expert testimony, Research grant / Funding (institution): Merck Serono; Advisory / Consultancy, Speaker Bureau / Expert testimony, Research grant / Funding (institution): Roche; Advisory / Consultancy, Research grant / Funding (institution): Beigene; Advisory / Consultancy, Speaker Bureau / Expert testimony, Research grant / Funding (institution): Bayer; Advisory / Consultancy, Speaker Bureau / Expert testimony, Research grant / Funding (institution): Servier; Advisory / Consultancy, Research grant / Funding (institution): Lilly; Advisory / Consultancy, Research grant / Funding (institution): Novartis; Advisory / Consultancy, Research grant / Funding (institution): Takeda; Advisory / Consultancy, Research grant / Funding (institution): Astellas; Advisory / Consultancy: Pierre Fabre; Research grant / Funding (institution): Genentech; Research grant / Funding (institution): Fibrogen; Research grant / Funding (institution): Amcure; Research grant / Funding (institution): Sierra Oncology; Research grant / Funding (institution): AstraZeneca; Research grant / Funding (institution): Medimmune; Research grant / Funding (institution): BMS; Research grant / Funding (institution): MSD; Speaker Bureau / Expert testimony: Amgen; Speaker Bureau / Expert testimony: Foundation Medicine. All other authors have declared no conflicts of interest.

Pulmonary Adenocarcinoma With Enteric Differentiation: Immunohistochemistry and Molecular Morphology.

Pulmonary adenocarcinoma with enteric differentiation (PAED) is a rare subtype of lung adenocarcinoma recently recognized in the WHO classification. It is defined as an adenocarcinoma in which the enteric component exceeds 50% and have to show the expression of at least 1 immunohistochemical marker of enteric differentiation. Although the definition of this tumor type is very important, above all in the differential diagnosis between a primary lung tumor and a metastasis of colorectal adenocarcinoma, this cancer still lacks a distinctive immunohistochemical and molecular signature. We recruited the largest series in the literature of PAEDs according to the morphology and the positivity for intestinal markers. Then, we evaluated the immunohistochemical and molecular profile of these adenocarcinomas. In our series, CDX-2 and CK7 were the immunohistochemical markers mostly expressed by PAEDs. There was an inverse relationship between the expression of pnuemocytes markers, such as TTF-1, and intestinal markers. Molecular analysis revealed KRAS as the most frequently mutated gene (>60% of cases), with very few cases harboring abnormalities affecting EGFR, BRAF, and ALK genes. PAEDs are morphologically very heterogenous. The immunohistochemical profile based on CDX-2 and CK7 positivity of PAEDs appears very robust to support this diagnosis, and it is applicable also on small biopsies. KRAS appears as the most important mutated gene in such tumors.