TTF-1 Expression Research Articles

Thyroid carcinoma with papillary and squamous features: Report of a case with histogenetic considerations

We present a case of an 82-year-old female with a painless left latero-cervical swelling, which increased in size over the course of 6 months, compressing adjacent organs. The histopathological examination, following dissection of the left thyroid lobe and ipsilateral cervical lymph nodes, yielded two intermingled morphologically distinct histotypes that included conventional papillary thyroid carcinoma (PTC) and poorly differentiated squamous cell carcinoma (SCC) with cystic features. The clinical presentation, the immunophenotype, and the genotype, especially of the malignant squamous component with partial expression of TTF1, marked expression of p63 and mutation of BRAF, were consistent with the diagnosis of a papillary thyroid carcinoma with squamous component. The possibility of a squamous cell carcinoma of unknown origin metastasizing to a primary papillary thyroid carcinoma cannot be completely ruled out. This particular presentation of thyroid carcinoma carries a poor prognosis in 20% of cases, with high recurrence rates and distant metastasis.

Five commonly used markers (p53, TTF1, CK7, CK20, and CK34βE12) are of no use in distinguishing between primary endocervical and endometrial adenocarcinomas in a tissue microarray extension study

The choice of appropriate therapeutic plans for primary endocervical adenocarcinomas (ECA) and endometrial adenocarcinomas (EMA) depends on the tumor's site of origin. Some panels of antibodies help to distinguish primary ECA from EMA. However, unexpected expressions of those markers often exist, which causes this diagnostic dilemma to be still unresolved. In this study, we investigate five commonly used monoclonal antibodies (p53, TTF1, CK7, CK20, and CK34betaE12) to evaluate their potential use in distinguishing between these two gynecologic malignancies. A tissue microarray was constructed using paraffin-embedded, formalin-fixed tissues from 35 hysterectomy specimens, including 14 ECA and 21 EMA. Utilizing the avidin-biotin (ABC) technique, tissue array sections were immunostained with the five aforementioned commercially available antibodies. Immunohistochemical (IHC) expressions of p53, TTF1, CK7, CK20, and CK34betaE12 were all nonsignificant (P>0.05) in frequency differences between the immunostaining results (positive vs. negative) in tumors from both the two primary adenocarcinomas (ECA vs. EMA). It is still uncertain which markers or panels would be the most appropriate for making diagnoses; hence, exploration of other useful markers, which make a definitive distinction between ECA and EMA merits further studies. This study, however, uncovered that the five commonly used monoclonal antibodies (p53, TTF1, CK7, CK20, and CK34betaE12) are of no beneficial value in distinguishing between primary ECA and EMA.

Desmocollin-3: a new marker of squamous differentiation in undifferentiated large-cell carcinoma of the lung

Lung cancer classification in small-cell and non-small-cell types was recently challenged by data on the differential efficacy of new cytotoxic agents in specific histotypes. An accurate histotype definition has therefore gained interest in both preoperative and surgical materials, but is a hard task especially in undifferentiated large-cell tumors lacking morphological signs of squamous or glandular differentiation. The responsiveness of these latter subtypes to new drugs apparently more selective for adenocarcinomas or squamous carcinomas is not fully understood, also due to the heterogeneity of diagnostic criteria for this tumor entity. Current immunohistochemical markers are not fully specific and new molecules are to be explored. On the basis of gene expression profiling data, reporting a remarkable differential expression of desmocollin-3 (a protein localized in desmosomal junctions of stratified epithelial) between adeno- and squamous cancers, we immunostained 62 cases of resected undifferentiated large-cell lung carcinomas for desmocollin-3 (and for TTF-1, p63 and mucin stain), to test its ability to identify a (residual) squamous phenotype, if present. Desmocollin-3 was expressed in almost half of the undifferentiated large-cell cancers and was mutually exclusive with TTF-1 (positive in 39%; the remaining 18 % of cases was double negative). Special large-cell carcinoma variants expressed desmocollin-3 in 6 of 6 basaloid, 7 of 12 clear-cell types, again mutually exclusive with TTF-1 expression. None of seven sarcomatoid carcinomas reacted for either marker. In 31 cytological samples diagnosed as ‘non-small-cell lung carcinoma’, desmocollin-3 was again mutually exclusive with TTF-1 and stained all squamous carcinomas, 1 of 19 adenocarcinoma only, and 50% of large-cell carcinoma (all histologically confirmed). This combined morphophenotypic approach may represent a valid adjunct (for both surgical and cytological samples) in the selection of patients with lung cancer to medical treatments tailored according to different efficacy in different lung carcinomas of the squamous, adeno- and large-cell types.

Immunohistochemical Staining for CDX-2, PDX-1, NESP-55, and TTF-1 Can Help Distinguish Gastrointestinal Carcinoid Tumors From Pancreatic Endocrine and Pulmonary Carcinoid Tumors

Well-differentiated neuroendocrine tumors (WDNET) of the gastrointestinal tract, pancreas, and lung are histologically similar. Thus, predicting the site of origin of a metastasis is not possible on morphologic grounds. Prior immunohistochemical studies of WDNET have yielded conflicting results, and pancreatic and duodenal homeobox factor-1 (PDX-1) has not previously been evaluated in this context. We therefore analyzed the expression of CDX-2, PDX-1, TTF-1, and neuroendocrine secretory protein-55 (NESP-55), a recently described member of the chromogranin family, in primary and metastatic WDNET. In total, 64 gastrointestinal carcinoids (5 stomach; 5 duodenum; 31 ileum; 11 appendix; and 12 rectum); 39 pancreatic endocrine tumors (PET); and 20 pulmonary carcinoid tumors were studied. PET were positive for NESP-55 (16/39) and PDX-1 (11/39); 3/31 also showed heterogeneous positivity for CDX-2. Ileal carcinoids were exclusively positive for CDX-2 (30/31) and negative for all other markers. Appendiceal carcinoids were uniformly positive for CDX-2 (11/11). All rectal carcinoids were negative for CDX-2 and TTF-1; 2/12 were positive for PDX-1, and 1/12 for NESP-55. The gastric and duodenal carcinoids were only positive for PDX-1 (7/10). TTF-1 positivity was confined to pulmonary carcinoids (7/20); 1/20 was positive for NESP-55; and all were negative for CDX-2 and PDX-1. NESP-55 and PDX-1 positivity, in the presence of negative CDX-2 and TTF-1, was 97% specific for PET. The sensitivity and specificity of CDX-2 positivity for predicting an ileal primary, when PDX-1, NESP-55, and TTF-1 were negative, was 97% and 91%, respectively. TTF-1 positivity was confined to pulmonary carcinoids in our study but was present in only about a third of cases. A panel of these 4 markers may be useful in predicting the primary site of metastatic WDNET.

Expression and role of TTF-1 in the rat suprachiasmatic nucleus

We have previously reported that TTF-1, a homeodomain-containing transcription factor, regulates circadian rhythm of pituitary adenylate cyclase-activating polypeptide gene expression in the rat hypothalamus. In this study we found that TTF-1 mRNA was specifically expressed in the rat suprachiasmatic nucleus (SCN) and colocalized with Period 2 (Per2), a circadian feedback loop controller. Interaction between TTF-1 and Per1 and Per2 was demonstrated by immunoprecipitation and immunoblot assays. Moreover, TTF-1 and Per proteins additively stimulated a transcriptional activity of angiotensinogen (AoGen) gene. TTF-1 also activated in vitro rhythm of AoGen transcription determined by secretary alkaline phosphatase (SEAP) reporter system in the NIH3T3 cells. These results suggest that TTF-1 plays a role in the circadian rhythm regulation of the AoGen gene expression via interacting with Per proteins in the rat SCN.

Thyroid transcription factor-1 (TTF-1/Nkx2.1/TITF1) gene regulation in the lung

TTF-1 [thyroid transcription factor-1; also known as Nkx2.1, T/EBP (thyroid-specific-enhancer-binding protein) or TITF1] is a homeodomain-containing transcription factor essential for the morphogenesis and differentiation of the thyroid, lung and ventral forebrain. TTF-1 controls the expression of select genes in the thyroid, lung and the central nervous system. In the lung, TTF-1 controls the expression of surfactant proteins that are essential for lung stability and lung host defence. Human TTF-1 is encoded by a single gene located on chromosome 14 and is organized into two/three exons and one/two introns. Multiple transcription start sites and alternative splicing produce mRNAs with heterogeneity at the 5' end. The 3' end of the TTF-1 mRNA is characterized by a rather long untranslated region. The amino acid sequences of TTF-1 from human, rat, mouse and other species are very similar, indicating a high degree of sequence conservation. TTF-1 promoter activity is maintained by the combinatorial or co-operative actions of HNF-3 [hepatocyte nuclear factor-3; also known as FOXA (forkhead box A)], Sp (specificity protein) 1, Sp3, GATA-6 and HOXB3 (homeobox B3) transcription factors. There is limited information on the regulation of TTF-1 gene expression by hormones, cytokines and other biological agents. Glucocorticoids, cAMP and TGF-beta (transforming growth factor-beta) have stimulatory effects on TTF-1 expression, whereas TNF-alpha (tumour necrosis factor-alpha) and ceramide have inhibitory effects on TTF-1 DNA-binding activity in lung cells. Haplo-insufficiency of TTF-1 in humans causes hypothyroidism, respiratory dysfunction and recurring pulmonary infections, underlining the importance of optimal TTF-1 levels for the maintenance of thyroid and lung function. Recent studies have implicated TTF-1 as a lineage-specific proto-oncogene for lung cancer.

MASH1: a useful marker in differentiating pulmonary small cell carcinoma from Merkel cell carcinoma

Merkel cell carcinoma is the cutaneous counterpart of small cell carcinoma, and the most important differential diagnosis is cutaneous metastasis of small cell carcinoma of the lung. There have been a handful of studies reporting on the utility of a variety of immunohistochemical markers that distinguish between the two entities. Achaete-scute complex-like 1 (MASH1, ASCL1) is important in the development of the brain and the diffuse neuroendocrine system including pulmonary neuroendocrine cells. A recent study, using a cDNA array, identified Mash1 as one of the best classifier genes to differentiate pulmonary small cell carcinoma from Merkel cell carcinoma. We immunohistochemically applied this finding to the diagnostic setting. A total of 30 cases of Merkel cell carcinoma and 59 cases of small cell carcinoma of the lung were immunostained with anti-MASH1 and TTF-1 antibodies. Of 59 small cell carcinomas, 49 (83%) expressed MASH1 in nuclear staining whereas out of 59 small cell carcinomas, 43 (73%) expressed TTF-1 in nuclear staining. MASH1 was completely negative in all 30 Merkel cell carcinomas whereas TTF-1 expression was seen in 1 of the 30 Merkel cell carcinomas (3%). MASH1 is a useful adjunct marker for differentiating small cell carcinoma of the lung from Merkel cell carcinoma.

TTF1 expression in non‐small cell lung carcinoma: association with TTF1 gene amplification and improved survival

Acquired chromosomal aberrations play an important role in tumour development and progression. Such genetic alterations occur in a significant proportion of non-small cell lung carcinomas (NSCLCs) and include amplification of 14q13.3, which contains the TTF1 gene. We asked whether TTF1 amplification is associated with increased TTF1 protein expression in NSCLCs, and whether TTF1 is associated with clinicopathological features, including patient survival. We used a FISH assay and quantitative immunohistochemical staining to interrogate a population-based cohort of 538 NSCLCs from Swiss patients for TTF1 amplification and protein expression. We found TTF1 amplification in approximately 13% of adenocarcinomas (ACs) and in approximately 9% of squamous cell carcinomas (SCCs) and TTF1 amplification was associated with increased TTF1 protein expression. High-level TTF1 expression was significantly associated with smaller tumour size, female gender and longer overall survival only among ACs (median survival 82 versus 28 months; p = 0.002). On multivariate analysis, high TTF1 expression was an independent predictor of favourable prognosis in patients with AC [hazard ratio, 0.56 (95% CI 0.38-0.83); p = 0.008]. We conclude that TTF1 amplification is a mechanism of high-level TTF1 expression in a subset of NSCLCs. When expressed at high levels, this routinely used diagnostic marker is also an independent biomarker of favourable prognosis in AC.

Intestinal Type and Endocervical-like Ovarian Mucinous Neoplasms are Immunophenotypically Distinct Entities

Ovarian mucinous neoplasm (OMN) is traditionally classified as either intestinal type or endocervical-like subtypes. The 2 subtypes represent different clinicopathologic characteristics. The immunophenotype of the 2 subtypes has not been adequately investigated. In this study, we investigated 14 intestinal type OMNs (borderline and adenocarcinoma) and 12 endocervical-like OMNs (borderline and adenocarcinoma) for their expression of PDX-1, CDX-2, CA-125, CK7, CK20, WT-1, D2-40, and TTF-1. We also included 15 colorectal adenocarcinomas metastatic in the ovary, as they may occasionally mimic OMN. The intestinal type OMNs were positive for PDX-1 (100%), CK7 (100%), CK20 (100%), CDX-2 (29%), whereas were negative for CA-125. The endocervical-like OMNs were positive for CA-125 (100%) and CK7 (100%), whereas were negative for CK20, PDX-1, and CDX-2. Metastatic colorectal adenocarcinomas were positive for CK20 (100%), CDX-2 (100%), and PDX-1 (33%), whereas were negative for CA-125 and CK7. All of the intestinal type and endocervical-like OMNs as well as metastatic colorectal adenocarcinomas were negative for WT-1, D2-40, and TTF-1. Our results demonstrated that the intestinal type and endocervical-like OMNs are immunophenotypically distinct entities. The 2 subtypes can be separated from metastatic colorectal adenocarcinoma by the different immunohistochemical profile of PDX-1, CA-125, CK7, CK20, and CDX-2. In the work-up of mucinous adenocarcinoma in the ovary or abdominal cavity, caution should be exercised in interpreting the possible primary site on the basis of the immunohistochemical profiles.

EGFR, TTF-1 and Mdm2 expression in stage III non-small cell lung cancer: A positive association

New biological factors have not been extensively studied in stage III NSCLC as yet. The aim of this retrospective study was to assess the association between the expression and the prognostic role on survival of four biological markers in stage III NSCLC. Clinical characteristics were retrieved from the patients charts. EGF-R, Mdm2, p53 and TTF-1 expressions were evaluated by immunohistochemistry by three independent observers. Cox multivariate model was used to assess the impact of clinical and biological factors on patients' survival. A total of 84 stage III NSCLC patients, treated between 03/1987 and 08/2003, were included in the study. There was a statistically significant association between the expression of TTF-1 and EGFR (p=0.01) or TTF-1 and Mdm2 (p=0.04). Positive expressions for EGFR or TTF-1 were almost mutually exclusive. The status EGFR+/TTF-1--was mainly found in squamous cell carcinoma (18 among 19tumours). In multivariate analysis, only treatment with curative intent was independently associated with better survival (p=0.0004). In stage III NSCLC, there was a significant association between TTF-1 and EGFR or TTF-1 and Mdm2. The status EGFR+/TTF-1--was associated with squamous cell carcinoma.

Islet 1 (Isl1) Expression is a Reliable Marker for Pancreatic Endocrine Tumors and Their Metastases

Tracing the origin of a metastasis of a neuroendocrine carcinoma is a challenge. The transcription factors Cdx2 and TTF1 have been found to be helpful in identifying well-differentiated neuroendocrine tumors of gastrointestinal and pulmonary origin, respectively. So far, such a marker is lacking for pancreatic neuroendocrine tumors (PETs) and metastases thereof. Islet1 (Isl1) is a transcription factor expressed in pancreatic islet cells. The aim of this study was (1) to test the specificity and sensitivity of Isl1 as a marker of PETs, and (2) to test the specificity and sensitivity of a panel of markers, including Isl1, Cdx2, and TTF1, for the localization of the primary. One hundred eighty-eight primary gastroenteropancreatic and pulmonary endocrine tumors and 49 metastases thereof were examined. Immunohistochemistry using antibodies directed against Isl1, Cdx2, and TTF1 was performed and the staining results were scored semiquantitatively. Isl1 proved to be a highly specific marker for pancreatic endocrine tumors. In 84 primary PET its specificity was 78.4% (sensitivity 74.3%) and in 18 metastases of PET the specificity reached 100% (sensitivity 77.8%). Strong Cdx2 staining showed a specificity for gastrointestinal origin of 83.9% (sensitivity 82%) in primary tumors and of 100% (sensitivity 40%) in metastases. Including weakly positive tumors lead to a decreased specificity but an increased sensitivity. TTF1 expression was detected in 2 PET and 1 ileal primary tumor only and was absent in all metastases of gastroenteropancreatic endocrine tumors. Isl1 is a reliable marker of pancreatic endocrine tumors and metastases thereof. It shows a comparable sensitivity and specificity as Cdx2 as a marker of ileal and appendiceal neuroendocrine tumors and their metastases. TTF1 is very rarely expressed in well-differentiated gastroentero-PETs. Therefore, the panel of Isl1, Cdx2, and TTF1 seems useful for examining metastases of well-differentiated endocrine carcinomas of unknown origin.

Prenatal treatment with retinoic acid accelerates type 1 alveolar cell proliferation of the hypoplastic lung in the nitrofen model of congenital diaphragmatic hernia

Retinoids play an important role in lung development. A recent study has demonstrated that prenatal treatment with retinoic acid (RA) stimulates alveologenesis in hypoplastic lungs in the nitrofen model of congenital diaphragmatic hernia (CDH). Furthermore, it has also been demonstrated that the differentiation from alveolar epithelial cells type II (AECs-II) into alveolar epithelial cells type I (AECs-I), which is the key process in lung development, is disturbed in this model. We hypothesized that retinoids promote alveologenesis by stimulating differentiation of AECs-II to AECs-I at the end of gestation; and therefore, we investigated the effect of RA on the pulmonary expression of intercellular adhesion molecule 1 (ICAM-1), a marker for AECs-I, and thyroid transcription factor 1 (Ttf-1), a marker for AECs-II, in nitrofen-induced hypoplastic lungs. Pregnant rats were exposed to either olive oil or 100 mg nitrofen on day of gestation (D) 9. Five milligrams per kilogram of RA was given intraperitoneally on D18, D19, and D20; and fetuses were recovered on D21. We had 4 study groups: control (n = 7), control + RA (n = 7), CDH (n = 6), and CDH + RA (n = 6). The expression of ICAM-1 and Ttf-1 was analysed in each lung by real-time reverse transcription polymerase chain reaction and immunohistochemistry. One-way analysis of variance test was used for statistical analysis. Expression levels of ICAM-1 were significantly reduced in CDH lungs compared with normal controls, whereas levels increased significantly in CDH group after the addition of RA (P < .05). Expression levels of Ttf-1 were significantly decreased in lungs from RA-treated CDH animals compared with CDH without RA (P < .05). The ICAM-1 and Ttf-1 immunoreactivity demonstrated similar pattern of expression in various groups. Our results demonstrate that prenatal treatment with RA accelerates AEC-I proliferation in the hypoplastic lung in CDH.

Podoplanin is a Better Immunohistochemical Marker for Sarcomatoid Mesothelioma Than Calretinin

Immunohistochemistry using a broad panel of markers is an invaluable tool for diagnosing sarcomatoid mesothelioma. Membranous podoplanin staining has been proposed as a specific and sensitive marker to distinguish epithelioid mesothelioma from adenocarcinoma. We found that cytoplasmic podoplanin staining was present in sarcomatoid mesotheliomas, and wanted to explore the reproducibility and specificity of this staining pattern. Immunohistochemistry for podoplanin, using 2 podoplanin antibodies (antipodoplanin and D2-40), was performed in 55 mesotheliomas (24 epithelioid, 18 sarcomatoid, and 13 biphasic), 80 pulmonary adenocarcinomas, 8 synovial sarcomas, and 16 sarcomatoid carcinomas. Expression of calretinin, vimentin, MOC31, and TTF-1 was also examined in all adenocarcinomas, sarcomatoid carcinomas, 7 synovial sarcomas, and 21 of the mesotheliomas. Calretinin staining performed previously on an additional 31 mesotheliomas was reviewed. Using membranous or cytoplasmic staining as indicative of positivity, we found that antipodoplanin and D2-40 each stained 84% of mesotheliomas (antipodoplanin: 46/55; D2-40: 38/44), including 72% of sarcomatoid mesotheliomas (antipodoplanin: 13/18; D2-40: 11/14). With antipodoplanin antibody, no staining was seen in the pulmonary adenocarcinomas (0/80, 0%) or the synovial sarcomas (0/8, 0%), and weak cytoplasmic staining was seen in only 1 sarcomatoid carcinoma (1/15, 7%). D2-40 showed similar results, staining 3% (2/80) of pulmonary adenocarcinomas, 13% (1/8) of synovial sarcomas, and 8% (1/13) of sarcomatoid carcinomas. Overall sensitivities and specificities were 84% and 99% for antipodoplanin, and 86% and 96% for D2-40. These findings suggest that cytoplasmic podoplanin expression may be useful in the diagnosis of sarcomatoid mesothelioma, although it should be used with caution on biopsy material.

Large Cell and Small Cell Neuroendocrine Bladder Carcinoma

We studied 44 cases of small cell bladder carcinoma (SCBC) and 2 cases of large cell neuroendocrine bladder carcinoma (LCNBC) to determine the immunohistochemical profile and biologic behavior. Thyroid transcription factor (TTF)-1, cytokeratin (CK)20, chromogranin A (CgA), synaptophysin, neuron-specific enolase (NSE), and Leu-7 studies were performed. TTF-1+ cases were stained for surfactant protein A (SP-A). The immunohistochemical profile for 44 SCBC cases was as follows: TTF-1+, 11 (25%); CK20+, 3 (7%); CgA+, 13 (30%); synaptophysin+, 22 (50%); NSE+, 35 (80%); and Leu-7+, 30 (68%), and for 2 LCNBC cases was as follows: TTF-1+, 2 (100%); CgA+, (50%); synaptophysin+, 1 (50%); NSE+, 2 (100%); and Leu- 7+, 2 (100%). All cases with TTF-1 expression were negative for SP-A, except 1 case. This case was a mixed SCBC with TTF-1 expression in the urothelial component, which also expressed SP-A. Immunohistochemical markers were not associated with survival. The prognosis of SCBC is relatively better than its pulmonary counterpart. LCNBC seems to be a rarely recognized entity. TTF-1 expression is not limited to small cell lung carcinoma.

Y1-01: Toward A New Histological Classification Of Lung Tumors

Y1-01: Toward A New Histological Classification Of Lung Tumors

P2-071: PLOD2 and TTF1 expression as prognostic variables in selection for adjuvant treatment in early stage lung adenocarcinoma

P2-071: PLOD2 and TTF1 expression as prognostic variables in selection for adjuvant treatment in early stage lung adenocarcinoma

MTP22-01: Neuroendocrine tumors

MTP22-01: Neuroendocrine tumors

Lineage-Specific Dependency of Lung Adenocarcinomas on the Lung Development Regulator TTF-1

Emerging evidence, although currently very sparse, suggests the presence of "lineage-specific dependency" in the survival mechanisms of certain cancers. TTF-1 has a decisive role as a master regulatory transcription factor in lung development and in the maintenance of the functions of terminal respiratory unit (TRU) cells. We show that a subset of lung adenocarcinoma cell lines expressing TTF-1, which presumably represent those derived from the TRU lineage, exhibit marked dependence on the persistent expression of TTF-1. The inhibition of TTF-1 by RNA interference (RNAi) significantly and specifically induced growth inhibition and apoptosis in these adenocarcinoma cell lines. Furthermore, a fraction of TTF-1-expressing tumors and cell lines displayed an increase in the gene dosage of TTF-1 in the analysis of 214 patients with non-small-cell lung cancer, including 174 adenocarcinomas, showing a tendency of higher frequency of increased gene copies at metastatic sites than at primary sites (P=0.07, by two-sided Fisher's exact test). These findings strongly suggest that in addition to the development and maintenance of TRU lineages in normal lung, sustained TTF-1 expression may be crucial for the survival of a subset of adenocarcinomas that express TTF-1, providing credence for the lineage-specific dependency model.

IFCT0401-bio trial: Predictive biological markers for disease control (DC) of patients with non-resectable, adenocarcinoma with bronchioloalveolar carcinoma features (ADC-BAC) treated with gefitinib

7653 Background: A French prospective multicentric phase II trial (IFCT0401) evaluated gefitinib as first-line treatment in non- resectable ADC-BAC. Tissue samples were collected for central pathological review and molecular analysis in attempt to identify biological markers associated with DC by gefitinib. Methods: Tumor samples were classified as BAC variants or ADC-other types according to the 2004 WHO histological classification and as non-mucinous or mucinous/mixed according to cytology. Immunohistochemistry was performed using antibodies against TTF1, Ki67, phosphorylated AKT, erbB2, and EGFR. Polysomy/amplification was examined for EGFR and erbB2. EGFR 18–21 and K-ras 2 exons were amplified and sequenced. Results: Tissue specimen were collected from 65 of the 88 eligible participants. This subgroup did not differ from the overall trial population in terms of sex ratio, proportion of non-smokers and DC rate. DC was achieved in 22/64 patients (DCR=34.4%, CI=[22–41]). 81% were BAC variants (n=50) and 19% ADC other types. Of the 50 BAC variants, half were non-mucinous and half mucinous. EGFR high polysomy/amplification was present in 6/40 samples (15%). EGFR exon 19, 20 and 21 mutations were detected in 6/57 (10.5%), 1/49 (2%) and 0/58 samples, respectively and K- ras mutation in 11/53 (20.7%). Expression of TTF1 (p&lt;0.0001) and EGFR (p=0.04) as well as polysomy/amplification of EGFR (p=0.04) were significantly higher in the non-mucinous than in the mucinous type. There was also a trend for more frequent detection of EGFR mutations among non-mucinous than mucinous type (p=0.08). DC with gefitinib was significantly associated with female gender (p=0.02), non- smoker status (p=0.03), non-mucinous subtype (p=0.006), high TTF1 expression (p=0.02) and EGFR mutation (p=0.0003). K-ras mutation was associated with progression (p=0.04). Conclusions: Among patients with histologically proven ADC-BAC who received gefitinib, female gender, non-smoker status, non-mucinous subtype, high TTF1 expression, and EGFR mutation are associated with DC, while K-ras mutation is associated with disease progression. Multivariate analysis will be released at ASCO meeting. No significant financial relationships to disclose.

Aberrant Expression of TTF-1 and Forkhead Factor HFH-4 in Atrophic Gastritis and Ciliated Metaplasia Suggests Gastric Broncho-Pulmonary Transdetermination

Aberrant Expression of TTF-1 and Forkhead Factor HFH-4 in Atrophic Gastritis and Ciliated Metaplasia Suggests Gastric Broncho-Pulmonary Transdetermination