Changes of cytokeratin and involucrin expression in squamous cell carcinomas of the skin during progression to malignancy

Loss of the laminin subunit alpha-3 induces cell invasion and macrophage infiltration in cutaneous squamous cell carcinoma

BACKGROUND

Cutaneous squamous cell carcinoma (cSCC) is a common cancer that invades the dermis through the basement membrane. The role of the basement membrane in poorly differentiated cSCC is not well understood.

OBJECTIVES

To study the effect that loss of the laminin subunit alpha-3 (α3) chain from the tumour microenvironment has on tumour invasion and inflammatory cell recruitment.

METHODS

We examined the role of the basement membrane proteins laminin subunits α3, β3 and γ2 in SCC invasion and inflammatory cell recruitment using immunohistochemistry, short hairpin RNA knockdown, RNA-Seq, mouse xenograft models and patient tumour samples.

RESULTS

Analysis of SCC tumours and cell lines using antibodies specific to laminin chains α3, β3 and γ2 identified a link between poorly differentiated SCC and reduced expression of laminin α3 but not the other laminin subunits investigated. Knockdown of laminin α3 increased tumour invasion both in vitro and in vivo. Western blot and immunohistochemical staining identified increased phosphorylated myosin light chain with loss of laminin α3. Inhibition of ROCK (rho-associated protein kinase) but not Rac1 significantly reduced the invasive potential of laminin α3 knockdown cells. Knockdown of laminin subunits α3 and γ2 increased monocyte recruitment to the tumour microenvironment. However, only the loss of laminin α3 correlated with increased tumour-associated macrophages both in xenografted tumours and in patient tumour samples.

CONCLUSIONS

These data provide evidence that loss of the laminin α3 chain in cSCC has an effect on both the epithelial and immune components of cSCC, resulting in an aggressive tumour microenvironment.

Immunohistochemical Studies of Cytokeratins and Differentiation Markers in Bovine Ocular Squamous Cell Carcinoma

Bovine Ocular Squamous Cell Carcinoma is considered the most common bovine tumour, causing significant economic losses, mainly by abattoir condemnations. To obtain a better insight into the genesis and neoplastic transformation, 19 samples collected at slaughter from Holstein Friesian cattle and diagnosed as Ocular Squamous Cell Carcinoma were studied. Tumours were histologically classified into three categories: poorly (26.3%), moderately (26.3%), and well differentiated (47.4%). Expression of keratins (MNF116 and LP34) and of cornified envelope precursors (involucrin and profilaggrin) was studied. Expression of MNF116 was observed in all carcinomas. LP34 immunostaining was seen in all but three carcinomas, one from each degree. Involucrin immunoreaction was observed in all but one poorly differentiated carcinoma. Profilaggrin was present in only two moderately differentiated carcinomas, in all but one well differentiated, and in all but one poorly differentiated. MNF116 is a useful marker to confirm the epithelial origin of the tumour and stain most neoplastic cells in these tumours. The expression of involucrin and LP34 demonstrates that, in all tumours, cells have reached the final program of differentiation, regardless of the grade. The expression of profilaggrin could indicate molecular changes during malignant transformation but their expression does not seem to be of diagnostic value.

Oncogenic ALK F1174L drives tumorigenesis in cutaneous squamous cell carcinoma

Here, we show for the first time that anaplastic lymphoma kinase (ALK), a receptor tyrosine kinase of the insulin receptor superfamily, plays a pivotal role in the pathogenesis of cSCC.

Cutaneous squamous cell carcinoma (cSCC) is the second most common skin cancer characterized by increased mortality. Here, we show for the first time that anaplastic lymphoma kinase (ALK), a receptor tyrosine kinase of the insulin receptor superfamily, plays a pivotal role in the pathogenesis of cSCC. Our data demonstrate that the overexpression of the constitutively active, mutated ALK, ALK^F1174L, is sufficient to initiate the development of cSCC and is 100% penetrant. Moreover, we show that cSCC development upon ALK^F1174L overexpression is independent of the cell-of-origin. Molecularly, our data demonstrate that ALK^F1174L cooperates with oncogenic Kras^G12D and loss of p53, well-established events in the biology of cSCC. This cooperation results in a more aggressive cSCC type associated with a higher grade histological morphology. Finally, we demonstrate that Stat3 is a key downstream effector of ALK^F1174L and likely plays a role in ALK^F1174L-driven cSCC tumorigenesis. In sum, these findings reveal that ALK can exert its tumorigenic potential via cooperation with multiple pathways crucial in the pathogenesis of cSCC. Finally, we show that human cSCCs contain mutations in the ALK gene. Taken together, our data identify ALK as a new key player in the pathogenesis of cSCC, and this knowledge suggests that oncogenic ALK signaling can be a target for future clinical trials.

Syringic acid may attenuate the oral mucosal carcinogenesis via improving cell surface glycoconjugation and modifying cytokeratin expression

Syringic acid (SRA) is an excellent anti-oxidant and anti-cancer property in various in vitro and in vivo studies. In the present study was modifying effect of SRA on 7,12-dimethylbenz(a)anthracene (DMBA) induced cell surface glycoconjugates (GCs) abnormalities in the plasma and buccal mucosa of golden Syrian hamster buccal pouch carcinogenesis (HBPCs). Topical application of DMBA three times a week for 10 weeks on the buccal pouches of the hamsters resulted in well developed squamous cell carcinoma. GCs status was assessed biochemically, histological and immunoexpression pattern of cytokeratin (CK) in the buccal mucosa of the DMBA treated hamsters. Elevated levels of GCs and CK expression were observed in DMBA alone treated hamsters. Oral pre-administration of SRA (50 mg/kg bw) positively modulates the GCs levels and CK expressions to near normal. The present findings suggested that SRA can protect cell surface GCs and CK expression during DMBA induced HBPCs.

Topics in histopathology of sweat gland and sebaceous neoplasms

This article reviews several topics regarding sweat gland and sebaceous neoplasms. First, the clinicopathological characteristics of poroid neoplasms are summarized. It was recently reported that one-fourth of poroid neoplasms are composite tumors and one-fourth are apocrine type lesions. Recent progress in the immunohistochemical diagnosis of sweat gland neoplasms is also reviewed. CD117 can help to distinguish sweat gland or sebaceous tumors from other non-Merkel cell epithelial tumors of the skin. For immunohistochemical differential diagnosis between sweat gland carcinoma (SGC) other than primary cutanesous apocrine carcinoma and skin metastasis of breast carcinoma (SMBC), a panel of antibodies may be useful, including p63 (SGC⁺ , SMBC^- ), CK5/6 (SGC⁺ , SMBC^- ), podoplanin (SGC⁺ , SMBC^- ) and mammaglobin (SGC^- , SMBC⁺ ). Comparison of antibodies used for immunohistochemical diagnosis of sebaceous carcinoma (SC) suggests that adipophilin has the highest sensitivity and specificity. Some authors have found that immunostaining for survivin, androgen receptor and ZEB2/SIP1 has prognostic value for ocular SC, but not extraocular SC. In situ SC is rare, especially extraocular SC, but there have been several recent reports that actinic keratosis and Bowen's disease are the source of invasive SC. Finally, based on recent reports, classification of sebaceous neoplasms into three categories is proposed, which are sebaceoma (a benign neoplasm with well-defined architecture and no atypia), borderline sebaceous neoplasm (low-grade SC; an intermediate tumor with well-defined architecture and nuclear atypia) and SC (a malignant tumor with invasive growth and evident nuclear atypia).

Potential Role of S100A8 in Cutaneous Squamous Cell Carcinoma Differentiation

Background

S100A8 is differentially expressed in various cell types and is associated with a number of malignant disorders. S100A8 may affect tumor biology. However, its role in cutaneous squamous cell carcinoma (SCC) is not well established.

Objective

This study aims to investigate the relationship between S100A8 and cutaneous SCC development.

Methods

We performed immunohistochemical staining to detect S100A8 expression in facial skin specimens of premalignant actinic keratosis (AK), malignant SCC, and normal tissues. In addition, we utilized postconfluence and high calcium-induced differentiation in a culture system model. Furthermore, we constructed a recombinant adenovirus expressing GFP-tagged S100A8 to investigate the role of S100A8 in SCC cell differentiation.

Results

S100A8 was significantly overexpressed in human cutaneous SCC compared to that in normal and AK tissues. S100A8 was gradually upregulated in SCC cells in a post-confluence-induced differentiation model. Overexpression of S100A8 in SCC cells induced by adenoviral transduction led to increased expression levels of differentiation markers, such as loricrin, involucrin, and filaggrin. S100A8 overexpression also increased loricrin and involucrin luciferase activity.

Conclusion

S100A8 regulates cutaneous SCC differentiation and induces well-differentiated SCC formation in skin.

Occludin is involved in adhesion, apoptosis, differentiation and Ca2+-homeostasis of human keratinocytes: implications for tumorigenesis

Tight junction (TJ) proteins are involved in a number of cellular functions, including paracellular barrier formation, cell polarization, differentiation, and proliferation. Altered expression of TJ proteins was reported in various epithelial tumors. Here, we used tissue samples of human cutaneous squamous cell carcinoma (SCC), its precursor tumors, as well as sun-exposed and non-sun-exposed skin as a model system to investigate TJ protein alteration at various stages of tumorigenesis. We identified that a broader localization of zonula occludens protein (ZO)-1 and claudin-4 (Cldn-4) as well as downregulation of Cldn-1 in deeper epidermal layers is a frequent event in all the tumor entities as well as in sun-exposed skin, suggesting that these changes result from chronic UV irradiation. In contrast, SCC could be distinguished from the precursor tumors and sun-exposed skin by a frequent complete loss of occludin (Ocln). To elucidate the impact of down-regulation of Ocln, we performed Ocln siRNA experiments in human keratinocytes and uncovered that Ocln downregulation results in decreased epithelial cell-cell adhesion and reduced susceptibility to apoptosis induction by UVB or TNF-related apoptosis-inducing ligand (TRAIL), cellular characteristics for tumorigenesis. Furthermore, an influence on epidermal differentiation was observed, while there was no change of E-cadherin and vimentin, markers for epithelial-mesenchymal transition. Ocln knock-down altered Ca²⁺-homeostasis which may contribute to alterations of cell-cell adhesion and differentiation. As downregulation of Ocln is also seen in SCC derived from other tissues, as well as in other carcinomas, we suggest this as a common principle in tumor pathogenesis, which may be used as a target for therapeutic intervention.

Identification and characterization of tumor-initiating cells in human primary cutaneous squamous cell carcinoma

Primary human squamous cell carcinoma (SCCa) are heterogeneous invasive tumors with proliferating outer layers and inner differentiating cell masses. To determine if tumor initiating cells (TIC) are present in SCCa, we utilized newly developed reliable in vitro and in vivo xenograft assays that propagate human SCCa, and demonstrated that a small subset of SCCa cells (~1%) expressing Prominin-1 (CD133) in the outer layers of SCCa were highly enriched for TIC (~1/400) compared to unsorted SCCa cells (TIC ~1/10⁶). Xenografts of CD133+ SCCa recreated the original SCCa tumor histology and organizational hierarchy, while CD133- cells did not, and only CD133+ cells demonstrated the capacity for self-renewal in serial transplantation studies. We present a model of human SCCa in which tumor projections expand with outer leading edges that contain CD133+ TIC. Successful cancer treatment will likely require that the TIC identified in cancers be targeted therapeutically. The demonstration that TIC are present in SCCa and are enriched in a CD133-expressing subpopulation to our knowledge has not previously been reported.

Spindle cell squamous cell carcinoma not expressing stratified but simple epithelial cytokeratin: efficacy of simple epithelial cytokeratin immunoreactivity

We present two cases of spindle cell squamous cell carcinoma, which were derived from solar keratosis and burn scar in two elderly Japanese patients, respectively. The tumors involved the whole dermis and subcutis in connection with the overlying epidermis. They were composed mainly of anaplastic spindle cells partially forming storiform patterns. The tumor cells were diffusely positive for vimentin and cytokeratin 8/18 (clone CAM5.2, simple epithelial cytokeratin), but negative for cytokeratin 1/5/10/14 (clone 34βE12, stratified epithelial cytokeratin). Ultrastructural analysis of a patient demonstrated desmosomes and tonofilaments in the tumor cells. Although spindle cell squamous cell carcinoma is usually positive for vimentin, detailed cytokeratin profile is controversial. The present cases revealed immunohistochemistry not expressing stratified but simple epithelial cytokeratin and vimentin. We should be reminded of the efficacy of simple epithelial cytokeratin immunoreactivity in spindle cell squamous cell carcinoma.

c-Jun promotes whereas JunB inhibits epidermal neoplasia

Deregulation of the activator protein 1 (AP1) family gene regulators has been implicated in a wide range of diseases, including cancer. In this study we report that c-Jun was activated in human squamous cell carcinoma (SCC) and coexpression of c-Jun with oncogenic Ras was sufficient to transform primary human epidermal cells into malignancy in a regenerated human skin grafting model. In contrast, JunB was not induced in a majority of human SCC cells. Moreover, exogenous expression of JunB inhibited tumorigenesis driven by Ras or spontaneous human SCC cells. Conversely, the dominant-negative JunB mutant (DNJunB) promoted tumorigenesis, which is in contrast to the tumor-suppressor function of the corresponding c-Jun mutant. At the cellular level, JunB induced epidermal cell senescence and slowed cell growth in a cell-autonomous manner. Consistently, coexpression of JunB and Ras induced premature epidermal differentiation concomitant with upregulation of p16 and filaggrin and downregulation of cyclin D1 and cyclin-dependent kinase 4 (CDK4). These findings indicate that JunB and c-Jun differentially regulate cell growth and differentiation and induce opposite effects on epidermal neoplasia.JID JOURNAL CLUB ARTICLE: For questions, answers, and open discussion about this article, please go to http://www.nature.com/jid/journalclub.

HPV8 early genes modulate differentiation and cell cycle of primary human adult keratinocytes

Human papillomaviruses (HPV) have been associated with the development of non-melanoma skin cancer (NMSC) but the molecular mechanisms of the role of the virus in NMSC development are not clearly understood. Abnormal epithelial differentiation seen in malignant transformation of keratinocytes is associated with changes in keratin expression. The purpose of this study was to investigate the phenotype of primary human adult keratinocytes expressing early genes of HPV8 with specific reference to their differentiation and cell cycle profile to determine whether early genes of HPV8 lead to changes that are consistent with transformation. The expression of HPV8 early genes either individually or simultaneously caused distinct changes in the keratinocyte morphology and induced an abnormal keratin expression pattern, that included simple epithelial (K8, K18, K19), hyperproliferation-specific (K6, K16), basal-specific (K14, K15) and differentiation-specific (K1, K10) keratins. Our results indicate that expression of HPV8 early genes disrupts the normal keratin expression pattern in vitro. Expression of HPV8-E7 alone caused polyploidy that was associated with decreased expression of p21 and pRb. Expression of individual genes or in combination differentially influenced cell morphology and cell cycle distribution which might be important in HPV8-induced keratinocyte transformation.

Cytokeratin 8/18 expression indicates a poor prognosis in squamous cell carcinomas of the oral cavity

BACKGROUND

Intermediary filaments are involved in cell motility and cancer progression. In a variety of organs, the expression of distinct intermediary filaments are associated with patient prognosis. In this study, we seeked to define the prognostic potential of cytokeratin and vimentin expression patterns in squamous cell carcinomas (SCC's) of the oral cavity.

METHODS

308 patients with histologically proven and surgically treated squamous cell carcinomas of the oral cavity were investigated for the immunohistochemical expression of a variety of intermediary filaments including high- and low-molecular weight cytokeratins (Ck's), such as Ck 5/6, Ck 8/18, Ck 1, CK 10, Ck 14, Ck 19 and vimentin, using the tissue microarray technique. Correlations between clinical features and the expression of Cytokeratins and vimentin were evaluated statistically by Kaplan-Meier curves and multivariate Cox regression analysis.

RESULTS

The expression of Ck 8/18 and Ck 19 were overall significantly correlated with a poor clinical prognosis (Ck 8/18 p = 0.04; Ck19 p < 0.01). These findings could also be reproduced for Ck 8/18 in primary nodal-negative SCC's and held true in multivariate-analysis. No significant correlation with patient prognosis could be found for the expression of the other cytokeratins and for vimentin.

CONCLUSION

The expression of Ck 8/18 in SCC's of the oral cavity is an independent prognostic marker and indicates a decreased overall and progression free survival. These results provide an extended knowledge about the role of intermediary filament expression patterns in SCC's.

Regulation of the human involucrin gene promoter by co-activator proteins

Stratified squamous epithelial cells undergo an orderly process of terminal differentiation that is characterized by specific molecular and morphological changes, including expression of the cornified envelope protein involucrin. Significant progress has been made in characterizing the upstream regulatory region of the involucrin gene. Binding sites for AP-1 (activator protein 1) and Sp1 transcription factors were shown to be important for involucrin promoter activity and tissue-specific expression. Defective terminal differentiation is often characterized by decreased or lack of involucrin expression. Recently, a dominant-negative construct of the transcriptional co-activator P/CAF [p300/CBP-associated factor, where CBP stands for CREB (cAMP-response-element-binding protein)-binding protein] was shown to inhibit involucrin expression in immortalized keratinocytes [Kawabata, Kawahara, Kanekura, Araya, Daitoku, Hata, Miura, Fukamizu, Kanzaki, Maruyama and Nakajima (2002) J. Biol. Chem. 277, 8099-8105]. Loss of expression or inactivation of other co-activators has also been demonstrated [Suganuma, Kawabata, Ohshima, and Ikeda (2002) Proc. Natl. Acad. Sci. U.S.A. 99, 13073-13078]. In the present study, we re-expressed CBP and P/CAF in immortalized keratinocyte lines that had lost expression of these co-activator proteins. Re-expression of these proteins restored calcium- and RA (retinoic acid)-responsive involucrin expression in these cells. RA and calcium signalling induced exchange of CBP and P/CAF occupancy at the AP-1 sites of the involucrin promoter. CBP and P/CAF inductions of the involucrin expression were not dependent on MEK (mitogen-activated protein kinase/extracellular-signal-regulated kinase kinase), p38, protein kinase C or CaM kinase (calcium/calmodulin-dependent kinase) signalling. Kinase-induced changes in involucrin promoter activity directly resulted from changes in AP-1 protein expression. We concluded that CBP and P/CAF are important regulators of involucrin expression in stratified squamous epithelial cells.

Acitretin treatment in (pre)malignant skin disorders of renal transplant recipients: histologic and immunohistochemical effects

BACKGROUND

The incidence of (pre)malignant skin lesions after renal transplantation is high. Acitretin treatment appears to decrease the number of new squamous cell carcinomas and ameliorates the aspect and reduces the number of actinic keratoses. However, no histologic and immunohistochemical studies have been performed to further substantiate these observations.

METHODS

In 33 renal transplant recipients, biopsies were taken before and after 3 months of treatment with acitretin in doses up to 0.4 mg/kg/day. Histologic and immunohistochemical parameters for dysplasia, epidermal thickness, proliferation, differentiation, apoptosis, and dermal inflammation were analyzed.

RESULTS

Following acitretin treatment, a significant reduction in epidermal thickness (P =.002) and a significant increase in normal differentiation parameter K10 (P =.02) was observed. Epidermal proliferation did not change, nor did apoptosis, inflammation, keratinocytic epidermal neoplasia score, or transglutaminase staining. At baseline, in 8 actinic keratoses, a single cell expression pattern of K13 and/or K19 was found. This was associated with high levels of parameters indicative of high-risk lesions (P <.05). After acitretin treatment, an increase in K13 (P =.006) and K19 (P =.05) was found, together with a change in expression towards a focal or band-like staining pattern.

CONCLUSION

Acitretin improves the aspect of actinic keratoses via alteration of keratinization, resulting in peeling of the stratum corneum. No significant change in proliferation was found, which may explain the rapid recurrence of actinic keratoses seen after cessation of acitretin treatment.

Detection of nonmelanoma skin cancer micrometastases in lymph nodes by using reverse transcriptase-polymerase chain reaction for keratin 19 mRNA

BACKGROUND

A new sensitive method for the detection of skin cancer micrometastases in lymph nodes is based on amplification of keratin 19 (K19) mRNA by reverse transcriptase-polymerase chain reaction (RT-PCR).

OBJECTIVES

To compare results of RT-PCR with those of histological examination in terms of the detection rate of skin cancer micrometastases.

METHODS

Twenty-six lymph nodes obtained from 13 patients with squamous cell carcinoma (SCC), eccrine porocarcinoma and Paget's disease were investigated by histological examination (haematoxylin and eosin sections) and RT-PCR. RT-PCR was performed on extracted RNA by using K19 primer pairs. RT-PCR products were visualized by ethidium bromide staining and confirmed by non-radioactive hybridization with K19-specific probes.

RESULTS

All of 10 histologically positive lymph nodes yielded the expected 460-bp band. Of the 16 histologically negative lymph nodes, one (6%) was found by RT-PCR to express K19 mRNA, indicating the presence of micrometastases which could not be detected by histological examination. A serial dilution study using RNA extracted from SCC cells mixed with RNA extracted from normal lymph node cells showed a detection sensitivity of K19 RT-PCR of 10-5 micro g cancer cell RNA in 1 micro g lymph node RNA. Nested RT-PCR showed a detection sensitivity of one tumour cell in 106 lymphocytes.

CONCLUSIONS

These results demonstrate the usefulness of K19 RT-PCR for the detection of skin cancer micrometastases in lymph nodes.

Squamous metaplasia induced by transfection of human papillomavirus DNA into cultured adenocarcinoma cells

BACKGROUND/AIM

It has been reported previously in cases of adenosquamous carcinoma of the lung in Okinawa, a subtropical island 2000 km south of mainland Japan, that the squamous cell carcinoma components were positive for human papillomavirus (HPV) by non-isotopic in situ hybridisation (NISH). The adenocarcinoma cells adjacent to the squamous cell carcinoma components were enlarged and also positive for HPV. This is thought to indicate that after adenocarcinoma cells are infected with HPV, they undergo morphological changes, and that "squamous metaplasia" follows. In this present study, the effects of HPV transfection into adenocarcinoma cells were examined. The relation between the region expressing the HPV gene and squamous metaplasia was also studied.

METHODS

Plasmid pBR322 containing HPV type 16 (HPV-16) was transfected into cultured colonic adenocarcinoma (DLD-1) and lung adenocarcinoma (PC-14) cells using the calcium phosphate method. Neomycin was used as a selection marker. The presence of HPV E1, E2, E4, E5, E6, E7, L1, and L2 mRNAs and also transglutaminase 1, involucrin, cyclin dependent kinases (CDKs), cyclins, caspases, apoptosis inducing factor, DNase gamma, Fas, and Fas ligand mRNAs in HPV transfected cells was investigated by means of reverse transcription polymerase chain reaction (RT-PCR). The G0-G1 cell population was analysed by flow cytometry. Morphological examination under light and electron microscopes was also carried out.

RESULTS

The virus transfected cells showed squamous metaplasia when they were injected into severe combined immunodeficient mice, expressing the high molecular weight keratin (Moll's number 1 keratin) and involucrin molecules immunohistochemically, and involucrin and transglutaminase I mRNAs by RT-PCR. The squamous metaplasia was most conspicuous in the HPV transfected DLD-1 cell when compared with HPV transfected PC-14 cells. Squamous metaplasia was most clearly demonstrated in one HPV transfected DLD-1 cell clone, which expressed not only E2 but also E6-E7 fusion gene mRNA. Viral L1 mRNA expression was absent in HPV transfected cell clones, and was not related to squamous metaplasia. The growth rate of HPV transfected cells was reduced. Transfection of the virus into the cultured adenocarcinoma cells increased the G0-G1 cell population greatly, as assessed by flow cytometer analysis. Furthermore, in the virus transfected cells, apoptosis was also observed by means of the terminal deoxynucleotidyl transferase mediated dUTP biotin nick end labelling method.

CONCLUSION

HPV transfection into adenocarcinoma cells induced clear squamous metaplasia. One of the HPV transfected cell clones that expressed E2 and E6-E7 fusion gene mRNA showed the squamous metaplasia particularly clearly, and apoptosis was also demonstrated.

Syringoid eccrine carcinoma: report of a case with immunohistochemical analysis of cytokeratin expression

Syringoid eccrine carcinoma is an extremely rare cutaneous malignant tumor, thought to be derived from eccrine sweat apparatus. We report a case of syringoid eccrine carcinoma occurring on the scalp of a 66-year-old woman and analyzed its cytokeratin expression immunohistochemically to clarify its histogenesis. The tumor consisted mainly of numerous small cords and nests extending from the reticular dermis to the subcutaneous tissue, which formed luminal or tubular structures mimicking the nests of syringoma. Immunohistochemical analysis revealed that most tumor cells expressed simple epithelial cytokeratins (CKs 7, 8, 18, 19) suggesting their sweat secretory differentiation, and that a small number of tumor cells showed an expression of stratified epithelial cytokeratins (CKs 5, 14) suggesting their ductal differentiation. We believe that the syringoid eccrine carcinoma of our case may differentiate mainly toward the sweat secretory cells rather than toward the dermal ductal cells.

Cytokeratin 14 expression in epithelial neoplasms: a survey of 435 cases with emphasis on its value in differentiating squamous cell carcinomas from other epithelial tumours

AIMS

The tissue distribution of cytokeratin 14 (CK14) in epithelial neoplasms is not well defined. We have evaluated 435 cases of epithelial neoplasm of various origins with cytokeratin 14 monoclonal antibody with special attention to possible use in differential diagnosis.

METHODS AND RESULTS

Immunohistochemistry (ABC-HRP method) was performed for detection of CK14. We found that the expression of cytokeratin 14 was generally restricted to: (i) the majority of cases of squamous cell carcinoma regardless of origin (67/74) and degree of differentiation; (ii) neoplasms with focal squamous differentiation, including endometrial, and ovarian adenocarcinoma, malignant mesothelioma and transitional cell carcinoma; (iii) thymoma (8/8); (iv) myoepithelial components of salivary gland pleomorphic adenoma (3/4); and (v) oncocytic neoplasms, including thyroid Hurthle cell adenoma (1/1) and salivary gland Warthin's tumour (2/2).

CONCLUSION

CK14 protein is a useful marker in differential diagnosis of squamous cell carcinomas.

Expression of involucrin by ocular surface epithelia of patients with benign and malignant disorders

PURPOSE

Keratinization of the ocular surface epithelium is associated with various disorders impairing vision. We immunohistochemically determined whether the ocular surface epithelia express involucrin, and whether its expression pattern may differ in benign vs. malignant disorders. Expression of cytokeratins was also examined to provide further information relative to the epithelial differentiation.

METHODS

We evaluated 17 specimens; 6 specimens of the normal ocular surface epithelia, 3 specimens from cases of conjunctival intraepithelial neoplasia (CIN), 6 of conjunctival squamous cell carcinoma (SCC) and 2 of conjunctivae from cases of superior limbic keratoconjunctivitis (SLK).

RESULTS

Corneal epithelium exhibited intracellular immunoreactivity for involucrin. Four of the 6 specimens of bulbar conjunctival epithelium showed involucrin immunoreactivity in the perimembranous region, whereas the fornical conjunctiva was negative. Cornified envelope in SLK specimens was positive for involucrin. The CIN showed its immunoreactivity in the perimembranous region in all levels of the hyperproliferative epithelium without keratinization, i.e., similar to the bulbar conjunctiva. The neoplastic cells of well-differentiated SCC showed involucrin in the perimembranous region, and those of moderately- to poorly-differentiated SCC have involucrin in their cytoplasm. The expression pattern of cytokeratins was unrelated to grade of malignancy in ocular SCC.

CONCLUSION

The epithelia of normal subjects and of CIN expresses involucrin without keratinization. In contrary, the keratinized SLK epithelium markedly expresses involucrin in the cornified envelope. The subcellular immunolocalization of involucrin in the ocular SCC may help in evaluating the differentiation, i.e., malignancy, of neoplastic cells.

Immunohistochemical observation of cytokeratins in keratinous cysts including plantar epidermoid cyst

Sixteen cases of epidermal cyst (EC) (6 cases of conventional EC and 10 cases of plantar epidermoid cyst (PEC)) and 9 cases of trichilemmal cyst (TC) were examined by an immunohistochemical technique using various antibodies against cytokeratins and human papilloma virus (HPV) in order to clarify their histogenesis. There was no difference in immunoreactivities between EC and PEC with or without HPV infection. In TC, the inner layers of the cyst wall were stained with the antibody E3 (CK17), and the outermost layer was stained with the antibodies 4.1.18 (CK8) and 170.2.14 (CK19). In PEC and EC, however, the cyst wall didn't react with these antibodies, and differentiation-specific cytokeratins were expressed in the inner layer. These results confirmed that the immunoreactivities of PEC and EC were identical to those of normal epidermis or infundibulum, and that those of TC were similar to the outer root sheath between the lower infundibulum and isthmus. Although PEC has been recently reported to originate from eccrine ducts, there was a significant difference in immunoreactivities between PEC and eccrine ducts. Furthermore, on the basis of the fact that sole skin has no hair follicles, PEC was speculated to originate from epidermal implantation.

A small proline-rich protein, spr1: specific marker for squamous lung carcinoma

We have identified a small proline-rich protein, spr1, which is a sensitive and specific marker for distinguishing squamous cancer from the other cell types of lung carcinoma. A rabbit antiserum against a 15-amino-acid peptide of the C-terminus of spr1 was prepared. The specificity of this antiserum was demonstrated in normal squamous tissues by Western blotting and immunohistochemical analysis. Expression of spr1 in 63 cases of formalin-fixed and paraffin-embedded human bronchogenic carcinoma was studied by immunohistochemical staining. For these 63 cases of bronchogenic carcinoma previously diagnosed by hematoxylin/eosin (H/E) staining, the number of spr1-positive cases/total number of H/E cases of each cell type of lung cancer were as follows: 20/20 of squamous carcinoma, 2/18 of adenocarcinoma, 4/14 of large-cell carcinoma, and 0/11 of small-cell lung carcinoma. Squamous differentiation evidenced by spr1 expression was substantiated by the presence of squamous features observed under transmission electron microscopy (TEM). We conclude that spr1 is a sensitive and specific marker for squamous bronchogenic carcinoma.

Differential expression of type I cytokeratins in hamster cheek pouch epithelium following treatment with dimethylbenzanthracene

Cytokeratin (CK) expression in untreated, paraffin-treated or dimethylbenzanthracene (DMBA)-treated hamster cheek pouch epithelium was investigated utilizing monoclonal antibodies AE1 or AE3, which react with type I or type II CKs, respectively, and by in situ hybridization utilizing type I CK-specific probes. The latter were isolated from a cDNA library of hamster cheek pouch mRNA and designated CK 13 and CK 10 based on their respective homologies (> 95% amino acids) with murine CK 13 and human CK 10. Treatment of hamster cheek pouch epithelium with DMBA resulted in increased expression of type I CK, detected immunohistochemically with monoclonal AE1, but decreased expression of type II CKs detected with AE3. Despite an overall increase in type I CKs, in situ hybridization demonstrated differential expression of type I CKs with altered distribution of CK 13 mRNA and reduced expression of CK 10 mRNA, providing additional sensitive markers for DMBA-associated changes in CKs. These changes were constant at 2 to 22 weeks in the pre-neoplastic and neoplastic epithelium following the initial application of DMBA.

Papillary eccrine adenoma: immunohistochemical studies of keratin expression

Despite various studies, there are serious disagreements about the cellular differentiation of papillary eccrine adenoma. In the present study, 2 specimens of papillary eccrine adenoma were analyzed by immunohistochemical techniques, using a panel of monoclonal antibodies against keratins, to elucidate its differentiation. Histopathologically, the tumor was composed of multiple tubular structures lined by two or more layers of epithelial cells. The luminal cells of the tubules were flattened or cuboidal. The former were noted in large dilated tubules. The latter were usually observed in small-to-moderate-sized tubules, and formed intraluminal papillary projections in some tubules. Immunohistochemically, there were two kinds of cuboidal cells in the luminal layers of the tubules. Most of the large dilated tubules and some of the small-to-moderate-sized tubules expressed immunophenotypes similar to those of the eccrine dermal duct. The other tubular structures, including the small tubules resembling those of syringoma, expressed immunophenotypes similar to those of the transitional portions between the dermal ducts and the secretory segments of eccrine glands. From the above comparative studies, papillary eccrine adenoma is considered to differentiate towards the dermal duct and the transitional portions between the dermal ducts and the secretory segments of eccrine glands.