Squamous Cell Differentiation Marker Research Articles

Unusual lesion on the vulva of a postmenopausal woman

Unusual lesion on the vulva of a postmenopausal woman

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.

Interaction between Esophageal Squamous Cell Carcinoma and Adipose Tissue in Vitro

Esophageal squamous cell carcinoma (ESCC) develops within the squamous epithelial layer and invades the submucosa to the subadventitia that has adipose tissue (AT). AT seems critical to ESCC progression, but the underlying mechanism is unknown. We aimed to address the association between ESCC and AT invitro. ESCC cells were cultured on rat or human subcutaneous AT-embedded or -non-embedded collagen gel. AT promoted the growth of ESCC cells and inhibited their apoptosis. AT promoted the expression of the squamous differentiation marker involucrin in ESCC cells. AT accelerated the expression of invasion-related factors in poorly differentiated ESCC cells only. AT promoted the expression of phosphorylated-insulin-like growth factor-1 receptor in ESCC cells, whereas it inhibited that of the human epidermal growth factor receptor 2. Insulin-like growth factor-1, but not leptin, adiponectin, or resistin, promoted and inhibited the growth and apoptosis of ESCC cells, respectively. In turn, ESCC cells decreased the production of these adipokines in AT and the number of preadipocytes and mesenchymal stem cell-like cells, which developed from AT. These results suggest that i) AT may influence the progression of ESCC with increased growth or invasion and decreased apoptosis through insulin-like growth factor-1/insulin-like growth factor-1 receptor signaling, ii) AT may affect human epidermal growth factor receptor 2-targeted therapy; and iii) the cancer cells may affect adipokine production in AT.

The Swiss Continence Foundation Award: promoting the next generation in neuro-urology and functional urology.

Neuro-urology and functional urology are usually under-represented in the oncology dominated urological world. However, the prevalence of lower urinary tract symptoms (LUTS) is high and will increase further due to the increasing ageing population 1. Also more and more neurological patients will require professional neuro-urological consultation and management due to the high prevalence and incidence of several neurological diseases with frequent and severe impairment of lower urinary tract (LUT) function. LUT dysfunction not only impairs the quality of life of affected patients but also decreases productivity at home and work, resulting subsequently not only in the directly related costs of diagnosis and treatment but also in a significant economic burden for each society and healthcare system 2-4. Hence, neuro-urology and functional urology are highly relevant medical specialties in great demand. Moreover, neuro-urology and functional urology are young, innovative, and highly dynamic disciplines bridging neurological, gynecological, gastroenterological, and urological aspects of diagnosis and management allowing a significant look beyond each medical specialty and thus offering many career options in the clinic and research or both. Only in recent decades has it been progressively appreciated that the bladder is more than just a simple sack storing and releasing urine. The bladder wall is literally ‘alive’ comprising highly interactive layers communicating through a variety of receptors and neurotransmitters 5. Also, we have learnt about the supraspinal network influencing LUT control and its alterations in disease or in response to interventions 6, 7. Despite such advances, many physiological and pathophysiological questions still remain unanswered. In addition, there is a limited choice of treatments and the existing treatments have resulted in only slight improvements. Hence, there is urgent need for more: More development and improvement of diagnostics and treatments, more basic understanding on the pathophysiology of LUT dysfunction, and, most importantly, more young clinicians and researchers taking care of patients and future research. We need young appropriately trained and highly motivated clinicians and researchers to build the future of this speciality. Thus, it is our duty to support and encourage young talents in neuro-urology and functional urology, to retain them in the field, and to attract more to join. The Swiss Continence Foundation Award (http://www.swisscontinencefoundation.ch) represents such support for young talents. It comes with prize money of CHF 10 000 and is awarded to the best of the candidates who have been invited from all incoming award applications to present their current work in neuro-urology and functional urology to an international expert jury and the auditorium of the International Neuro-Urology Meeting. This year, The Swiss Continence Foundation Award has been awarded for the second time during the International Neuro-Urology Meeting in Zürich, Switzerland (Figs 1,2) and the prize-winning work of Véronique Phé entitled ‘Foxp3 expression serves as a marker of squamous cell differentiation and aggressive pathology of urothelial carcinomas in neurological patients’, is published in this BJUI supplement 8. Assembly of the award jury and award candidates at The Swiss Continence Foundation Award ceremony 2014. The invited candidates presented their current work in neuro-urology and functional urology during the 3rd International Neuro-Urology Meeting, 28–30 August 2014 in Zürich, Switzerland. From left to right, back row: Thomas M. Kessler, Ulrich Mehnert, Gommert A. van Koeveringe, Emmanuel Chartier-Kastler, Helmut Madersbacher, Francisco Cruz, Véronique Phé, Claudius Füllhase, Bahareh Abtahi. Front row: Jetske van Breda, Katarina Tudor, Tom Macrelissen, Saladin H. M. Alloussi, Mohammad Rahnama'i. The Chairmen of The Swiss Continence Foundation together with the current Swiss Continence Foundation Award 2014 winner Véronique Phé and the very first award winner form last year, Claudius Füllhase. All Swiss Continence Award winners become members of the Swiss Continence Foundation Award Alumni Circle and will be invited to all future International Neuro-Urology Meetings as guests of honour. From left to right: Thomas M. Kessler, Véronique Phé, Claudius Füllhase, Ulrich Mehnert. It was a great pleasure for all to have these young talents in the field among the more established experts, thereby providing them a platform for knowledge exchange, making new contacts, and career building. We are delighted to announce next year's Award and encourage all young (age ≤35 years) clinicians and researchers but also all research group leaders and clinical programme directors working in the field of neuro-urology and functional urology to motivate their suitable candidates to apply for The Swiss Continence Foundation Award 2015. Detailed application criteria are available at http://www.swisscontinencefoundation.ch. The authors declare that they have no conflict of interest.

Ovarian Basaloid Carcinoma with Shadow Cell Differentiation

So-called shadow cell differentiation (SCD) is typical for pilomatrixoma and other skin lesions with follicular differentiation, but it was rarely described also in some visceral carcinomas. We report a case of ovarian basaloid carcinoma with SCD. The tumor presented as a 14 cm ovarian mass in a 45-year-old woman, and therefore the adnexectomy and hysterectomy were performed. The tumor was of high stage. Multiple metastases were found in the liver, retroperitoneal and mediastinal lymph nodes, and the lung. Histologically, the tumor showed a pattern of high-grade basaloid carcinoma with numerous shadow cells. Extensive histologic examination did not reveal any glandular or preexisting teratoma component. Immunohistochemically, the tumor expressed markers of squamous cell differentiation, such as p63, cytokeratin 5/6, and high-molecular-weight keratin. Cytokeratin 7 and CA125 were positive in scattered cells of the lesion. Estrogen and progesterone receptor, vimentin, and p53 were negative. Beta-catenin showed nuclear and cytoplasmic positivity, indicating possible tumor proliferation/differentiation via Wnt signaling pathway. To our knowledge, SCD in basaloid carcinoma of the ovary was not described before. In addition to the description of the case, we review the literature on SCD in visceral carcinomas.

HPV16 E2 Is an Immediate Early Marker of Viral Infection, Preceding E7 Expression in Precursor Structures of Cervical Carcinoma

The viral E2 gene product plays a crucial role in the human papillomavirus (HPV) vegetative cycle by regulating both transcription and replication of the viral genome. E2 is a transcriptional repressor of the E6 and E7 viral oncogenes for HPV types 16 and 18, which are involved in cervical cancers. Using new polyclonal antibodies against the HPV16 E2 protein, we showed that E2 is expressed at various precursor stages of cervical carcinoma by immunohistochemistry on paraffin-embedded clinical samples. E2 was found to be highly expressed in the nuclei and cytoplasm of cells forming the intermediate and upper layers of cervical intraepithelial neoplasia (CIN). We could show that the expressions of E2 and p16(INK4a) (surrogate marker for oncogenic E7 expression) were exclusive in most of the cases, thus implying that E2 is not expressed together with high levels of E7. Moreover, we found that E2 is expressed in a subset of columnar cells adjacent to the CIN. We could show that expression of E2 is topologically distinct from the proliferation markers p63 and Ki67, whereas it coincides with the expression of cytokeratin K13, a marker of squamous cell differentiation. Expression of E2 also topologically coincides with episomal amplification of viral genomes in the upper layers of CIN1. These in vivo data thus validate previous assumptions of the crucial role of E2 in the early steps of HPV infection and of its negative link with expression of the viral E6 and E7 oncogenes.

Baseline thymidylate synthase expression according to histological subtypes of non-small cell lung cancer

7521 Background: In non-small cell lung cancer (NSCLC) baseline thymidilate synthase (TS) levels are higher in squamous cell carcinoma (SCC) compared to adenocarcinoma (AC) and randomized clinical trials have shown a selective benefit for patients with non-squamous histology treated with pemetrexed, a TS-inhibiting agent. TS expression in undifferentiated large cell carcinoma (LCC) is unknown. Methods: TS expression at both mRNA (using tissue microdissection and qRT-PCR) and protein (through immunohistochemistry, IHC) levels was tested in 34 surgically resected LCC (stage I=20,II=6,IIIa=8) and compared with TS expression in surgical cases of SCC (n= 31) and AC (n=40). In addition other comparisons were made: a) TS protein expression with Ki-67 index; b) TS mRNA and E2F1 transcription factor mRNA; c) in all histotypes TS protein level with desmocollin-3 (DSC-3) immunostaining, a marker of squamous cell differentiation. TS expression level was assessed in a group of patients (n=22) with cytological diagnosis of NSCLC-NOS (not otherwise specified) and compared with TS data in tissue specimens obtained through subsequent bronchial biopsy or surgical resection. Results: Significantly higher median TS levels in LCC compared to AC (p<0.001 for both mRNA and protein values) and SCC compared to AC (p=0.002 mRNA, p<0.001 protein) were detected. A strong correlation between TS mRNA and protein levels were found (p<0.001) in SCC and AC, but not in LCC. TS and both Ki-67 and E2F1 were significantly correlated in AC and SCC (p=0.003 and p=0.05, respectively), but in LCC no correlation was found. In LCC, significantly higher TS levels were observed in DSC3-positive compared to DSC3-negative tumors (p=0.02). A significant correlation between TS IHC scores in matched cytological and corresponding tissue specimens was observed (p<0.001). Conclusions: This study demonstrates and confirms the: a) differential expression of TS among the NSCLC histotypes; b) lack of DSC-3 immunoreactivity in LCC is associated with lower TS expression; c) assessment of TS by IHC in cytological specimens correlates with the corresponding tissue TS expression. [Table: see text]

The Role of Desmoglein-3 in the Diagnosis of Squamous Cell Carcinoma of the Lung

Results from several microarray-based studies have led to the identification of up-regulated expression levels of the DSG3 gene in pulmonary squamous cell carcinomas (SQCCs). The purpose of this study was to determine the role of DSG3 expression in the diagnosis of SQCCs of the lung and to compare DSG3 with p63, CK5, and CK6, as markers of squamous cell differentiation. Expression of DSG3 mRNA was evaluated in bulk laser capture microdissection-derived microarray data and by quantitative reverse transcription PCR on both SQCCs and adenocarcinomas. Expression levels of p63, CK5, and CK6 were evaluated in microarray data from the same set. An immunohistochemical study using antibodies directed against DSG3, p63, and CK5/6 was also performed. DSG3 was over-expressed in SQCCs but had very limited expression in both adenocarcinomas and non-neoplastic lungs. The microarray data showed that DSG3 had a sensitivity and specificity of 88% and 98%, respectively, in detecting SQCC versus adenocarcinoma. In comparison, sensitivity and specificity was 92% and 82% for p63, and 85% and 96% for CK5, respectively. The correlation coefficient between the microarray and immunohistochemical data for these genes was greater than or equal to 0.9. Using immunohistochemistry, sensitivity and specificity of DSG3 for lung cancers were 98% and 99%, respectively. Therefore, DSG3 can be a useful ancillary marker to separate SQCC from other subtypes of lung cancer.

Expression of G1 cell cycle markers and the effect of adenovirus-mediated overexpression of p21Waf-1 in squamous cell carcinoma of the esophagus.

To determine the crucial abnormality in the cell cycle regulatory proteins in human squamous cell carcinoma of the esophagus, we examined the cell growth ratio (CGR) and basal expression levels of G1 cyclins (cyclin D1, cyclin E), cyclin-dependent kinase (cdk) 2, cdk4, proliferating cell nuclear antigen (PCNA), and p21Waf-1 using 9 cell lines (KE3, KE4, TE8, TE9, TE10, TE11, YES1, YES2, and YES6). Western blotting revealed an inverse linear correlation between the basal levels of p21Waf-1 expression and CGR. The protein levels of G1 cyclins, cdks, and PCNA did not coordinately reflect the CGR. There was no relationship between p21Waf-1 expression levels and mutation of the p53 gene. Next, when the cells were stimulated with serum 48 h after the starvation, stimulated levels of the above G1 cell cycle markers were variously observed among cell lines irrespective of CGR. Serum stimulation markedly induced phosphorylated Rb in TE9 (a high CGR cell line, CGR>2.0), but not in KE4 (a low CGR cell line, CGR<1.5). Furthermore, adenovirus-mediated expression of exogenous p21Waf-1 effectively reduced cell growth in KE3 and TE9 (high CGR cell lines), but not in KE4 and TE11 (low CGR cell lines). p21Waf-1-mediated growth suppression was associated with the induction of involucrin, a marker of squamous cell differentiation. Our data suggested that the basal level, but not the stimulated level, of p21Waf-1 expression play a pivotal role in abnormal growth in human squamous cell carcinoma of the esophagus.

Phorbol Ester-induced Expression of Airway Squamous Cell Differentiation Marker, SPRR1B, Is Regulated by Protein Kinase Cδ/Ras/MEKK1/MKK1-dependent/AP-1 Signal Transduction Pathway

The transcriptional induction of SPRR1B by phorbol 12-myristate 13-acetate (PMA) is mainly mediated by the first -152-base pair 5'-flanking region containing two functional AP-1 sites. In this study, we have analyzed the signaling pathways that mediate the induction in tracheobronchial epithelial cells. PKC inhibitor ablated PMA-stimulated expression of endogenous SPRR1B and reporter gene expression driven by SPRR1B promoter. PKC activator promoted the transcription. The dominant negative protein kinase Cdelta (dn-PKCdelta) and rottlerin (PKCdelta inhibitor) completely suppressed PMA-stimulated promoter activity. dn-Ras or dn-MEKK1 inhibited PMA-stimulated promoter activity, while their corresponding constitutively active mutants augmented it. dn-c-Raf-1 did not have any effect on reporter gene expression. Since MEKK1 activates multiple parallel pathways, we examined involvement of JNK/SAPK, p38, and MKK1 in promoter regulation. Co-expression of the dominant negative forms of MKK4, MKK7, JNK/SAPK, MKK3, MKK6, or p38alpha did not suppress PMA-stimulated reporter gene expression. However, MKK1 inhibitors UO126 and PD98095 suppressed gene expression. Consistent with this, expression of dn-MKK1 strongly suppressed PMA-stimulated promoter activity, while the constitutively active MKK1 augmented it. However, MKK1-mediated induction of SPRR1B probably does not depend on extracellular signal-regulated kinases 1 and 2, suggesting the requirement of another kinase(s). dn-c-Jun mutants abolished PMA-stimulated expression supporting an important role for AP-1 proteins in SPRR1B expression. Together, these results suggest that a PKCdelta/Ras/MEKK1/MKK1-dependent/AP-1 pathway regulates the PMA-inducible expression of the SPRR1B in tracheobronchial epithelial cells.

Expression of human squamous cell differentiation marker, SPR1, in tracheobronchial epithelium depends on JUN and TRE motifs.

Expression of human squamous cell differentiation marker, SPR1, in tracheobronchial epithelium depends on JUN and TRE motifs.

Expression of Human Squamous Cell Differentiation Marker, SPR1, in Tracheobronchial Epithelium Depends on JUN and TRE Motifs

Tracheobronchial epithelial (TBE) cells that normally do not express the squamous cell differentiation marker gene, SPR1, can be induced to produce it by 12-O-tetradecanoylphorbol-13-acetate (TPA). The regulation of SPR1 gene expression by TPA occurs, in part, at the transcriptional level in primary human and monkey TBE cells. Using a transient transfection assay, we observed that TPA stimulates the activity of the reporter gene, chloramphenicol acetyltransferase, by 2-4-fold in transfected TBE cells. However, this chloramphenicol acetyltransferase activity is cell type-specific with significantly less activity in transformed epithelial cell lines and no activity in non-epithelial cell types. TPA-dependent stimulation can also be demonstrated by co-transfection with plasmid DNAs that overexpress the JUN family of proteins, especially c-JUN. Overexpression of c-JUN and TPA treatment synergistically stimulate the SPR1 promoter activity by more than 40-fold. Deletion analysis of the promoter region demonstrates that the DNA fragment of the first 98 base pairs of the 5'-flanking region contains the basal promoter activity, while the region between -162 and -96 contains the cis-enhancer elements for both the basal and TPA/c-JUN-stimulating promoter activities. This observation is supported by in vivo genomic footprinting studies that reveal persistent protections in the following motifs of this region: -141 TRE, -131 GT, -123 ETS-like, and -111 TRE-like motifs and in the enhanced protections in -141 TRE and -111 TRE-like motifs in cells after the TPA treatment. Site-directed mutagenesis in this region demonstrates the involvement of both -141 TRE and -111 TRE-like motifs in TPA/c-JUN-dependent stimulation as well as enhanced basal transcriptional activity. However, it is primarily the -111 TRE-like motif that is involved in the mediation of the enhanced basal promoter activity of the human SPR1 gene. These results are further supported by gel mobility shift assays that demonstrate the involvement of c-JUN and these TRE motifs in the formation of the DNA-protein complex.

Expression of a squamous cell marker, the spr1 gene, is posttranscriptionally down-regulated by retinol in airway epithelium.

Vitamin A (retinol) is required for the normal mucociliary differentiation of respiratory epithelium. A depletion of vitamin A promotes squamous cell metaplasia. To understand how vitamin A suppresses squamous cell differentiation, the expression of a squamous cell differentiation marker, the small proline-rich protein gene (spr1), was studied in cultured monkey tracheobronchial epithelial (TBE) cells. The expression of the spr1 gene was inhibited about 40 fold by retinol. The mRNA levels of the spr1 gene started to decline within 6 h of retinol treatment and reached a minimum level after 7 days. The inhibition by retinol was concentration dependent and did not require concurrent protein synthesis. The inhibition of the spr1 mRNA by retinol was not due to a decrease in the transcription rate of its gene but due to a decrease in its stability, as determined by nuclear run-on assays and mRNA half-life measurement, respectively. This result was further supported by a DNA transfection study using a chimeric construct containing the spr1 promoter region and the chloramphenicol acetyltransferase (CAT) reporter gene. The CAT activity in transfected cells was not inhibited by retinol. These results suggest that spr1 gene expression is posttranscriptionally down-regulated by retinol.

A Small Proline-rich Protein Regulated by Vitamin A in Tracheal Epithelial Cells Is Induced in Lung Tumors

In cell-free translations of RNA from primary cultures of pig trachea surface epithelial cells, we observed that a 20 kD proline-rich protein (sPRP) is induced during culturing (Biochem. Biophys. Res. Commun. 1990; 172:1304-1309). Subsequently, a cDNA encoding sPRP has been cloned from pig tracheal cell mRNA and sequenced. This cDNA shows a high similarity to cDNAs cloned from monkey tracheal cells cultured in vitamin A-free medium and from UV-irradiated human epidermal keratinocytes. Amino acid sequences from these cDNAs are exceptionally rich in proline, glutamine, cysteine, and lysine but contain no aromatic amino acids. Two repeats of 12 amino acids on the N-terminus are followed by multiple 8 amino acid repeats. When compared with monkey trachea and human keratinocyte cDNAs, the sPRP cDNA from pig trachea has an additional 24 bp nucleotide repeat. Antiserum raised to a synthetic peptide (23 amino acids) on the C-terminus of sPRP (C23-antiserum) reacted with the 20 kD sPRP in immunoprecipitations from cell-free translations. On Northern blot analysis, sPRP cDNA hybridized to RNAs of similar sizes in tracheal cells from cat, rabbit, and lamb. sPRP was not detected in tracheal cells that were cultured with 10(-9) M arotinoid. Since sPRP is considered a putative squamous cell differentiation marker, experiments using lung tumors were performed. sPRP mRNA levels were dramatically increased in squamous lung tumors that were induced by injecting hamsters with 4-(methylnitrosamino)- 1-(3-pyridyl)-1-butanone, a tobacco-specific nitrosamine. In situ hybridization with tissue sections prepared from these lung tumors revealed that cells around the keratin pearls contained high levels of sPRP mRNA.

Identification of a new squamous cell differentiation marker and its suppression by retinoids.

Rabbit tracheobronchial epithelial cells (RbTE) can undergo squamous cell differentiation under defined culture conditions and, therefore, have been used as a model to study the regulation of squamous cell differentiation markers. In the present study, we identified a 20-kDa protein, designated rSQ20, in the serum-free growth medium conditioned by RbTE cells undergoing squamous cell differentiation. The protein was also found in extracts of squamous differentiated cells. rSQ20 was labeled by cells incubated with [35S]methionine but not with [3H]glucosamine, suggesting that it is not a glycoprotein. Undifferentiated cells did not produce this protein. rSQ20 was detected in the conditioned medium of RbTE cells after they reached a confluent and growth-arrested state, and thereafter its level increased markedly and concurrently with an increase in type I (epidermal) transglutaminase, an established marker of squamous cell differentiation. rSQ20 found in concentrated conditioned medium of squamous differentiated RbTE cells was eluted from a gel filtration column as a protein of 20 kDa, similar to that found by gel electrophoresis under denaturing conditions, suggesting that it is not a multimeric protein. A protein with an apparent molecular weight of 16 kDa (rSQ16), probably the product of partial proteolysis of rSQ20, was often found in various amounts in the conditioned medium of differentiated RbTE cells. beta-All-trans retinoic acid and other vitamin A analogues (retinoids), which suppress squamous cell differentiation, inhibited the expression of rSQ20 in RbTE cells. RbTE cells immortalized by transfection with SV40 large T antigen as well as malignantly transformed derivatives obtained from the immortalized cells by further transfection with v-Ha-ras secreted SQ20 and SQ16 when grown to high cell densities although their squamous differentiation was impaired. An analogous protein with an apparent molecular weight of 16 kDa, designated hSQ16, was detected in the medium of differentiated normal human bronchial epithelial (NHBE) cells and normal human epidermal keratinocytes (NHEK). No such protein could be detected in the medium in which undifferentiated NHBE or NHEK cells were grown. These results suggest that rSQ20 and hSQ16 are new markers of squamous cell differentiation.

Retinoic acid suppression of squamous differentiation in human head-and-neck squamous carcinoma cells

Retinoids (vitamin A analogues) inhibit the squamous differentiation of normal and malignant epithelial cells. This study investigated the ability of the head-and-neck squamous-cell carcinoma (HNSCC) cell line 1483 to undergo squamous differentiation in the absence and presence of beta-all-trans retinoic acid (RA). The growth of these cells in culture is accompanied by an increase in keratinocyte transglutaminase, involucrin and keratin KI, 3 established markers of squamous cell differentiation. Higher levels of these differentiation markers were detected in cells cultured in delipidized serum (DLS), from which endogenous retinoids have been extracted, than in cells cultured in fetal bovine serum (FBS), which contains retinoids. Treatment with I microM RA decreased the levels of the various differentiation markers in cells cultured in either FBS or DLS as revealed by immunofluorescent labelling of permeabilized cells and by immunoblotting of cell extracts using specific monoclonal or polyclonal antibodies. The cells' ability to cross-link proteins to form envelopes under the plasma membrane was stimulated in the presence of calcium ionophore but inhibited by RA. These results indicate that the malignant 1,483 HNSCC cells recapitulate the main characteristics of normal squamous-cell differentiation in culture and that RA suppresses this differentiation as it does in normal keratinizing epithelial cells.

Tubular Adenoma of the Gallbladder with Squamoid Spindle Cell Metaplasia:Report of Three Cases with Immunohistochemical Study

Three cases of tubular adenoma of the gallbladder with squamoid spindle cell metaplasia are reported. Two of the three patients, who were middle-aged Japanese, had a solitary polyp in the gallbladder, and the other had three polyps. All the lesions were detected incidentally by ultrasonography. The polyps were pedunculated with a fine or frail stalk, and ranged from 0.5 to 3.9 cm in diameter. Histologically, they were tubular adenomas accompanied by scattered foci composed of a compact collection of short-spindle or oval cells with mild atypia. These cells did not retain intercellular bridges, and lacked intracellular keratinization. Immunohistochemically, the spindle cells stained positively for high-molecular-weight cytokeratin (EAB 903, a marker of squamous cell differentiation), whereas adenoma cells lining the tubules were negative for this antigen. Therefore, the spindle cell component is considered to represent squamoid metaplasia of adenoma cells.

Increase in cholesterol sulfotransferase activity during in vitro squamous differentiation of rabbit tracheal epithelial cells and its inhibition by retinoic acid.

It has previously been demonstrated that rabbit tracheal epithelial cells in primary culture undergo terminal differentiation at confluence to yield cornified cells much in analogy to epidermal keratinocytes and that one biochemical marker of this process seems to be the accumulation of cholesterol sulfate by the cells. The current work addresses the possible causes of this accumulation. Our studies show that the stimulation of cholesterol sulfate is paralleled by an increased activity of the biosynthetic enzyme cholesterol sulfotransferase. Squamous differentiated cells exhibited 20- to 30- fold higher levels of this enzyme activity than that in undifferentiated cells. As with other markers of squamous cell differentiation, the increase in cholesterol sulfotransferase can be prevented by the inclusion of retinoids in the cell culture medium. Inhibition of sulfotransferase levels can be observed at concentration of retinoic acid as low as 10(-11) M. The enzyme activity is optimal at pH 7 in buffers containing 0.2 M NaCl and 0.01% Triton X-100. Apparent Michaelis constants for the substrates 3'-phosphoadenosine-5'-phosphosulfate and cholesterol are 1 microM and 0.6 mM, respectively. Our results indicate that the increase in cholesterol sulfotransferase is the proximate cause for the accumulation of cholesterol sulfate in rabbit tracheal epithelial cells during squamous cell differentiation.

Ultrastructural investigation of anaplastic salivary gland carcinomas in Eskimos.

Ultrastructural investigation of 19 malignant lymphoepithelial salivary gland tumors in Greenland Eskimos disclosed evidence of epithelial origin of the tumor cells in 18 cases. Furthermore, tumor cells exhibited markers of squamous cell differentiation in 16 cases. Signs of adenomatous differentiation were never encountered. Thus, the malignant lymphoepithelial tumor of salivary glands is the ultrastructural counterpart to the nasopharyngeal anaplastic carcinoma (malignant lymphoepithelioma), both being high-grade squamous cell carcinomas.