Jun Cheng

Emergence of keratin 17 vs. loss of keratin 13: Their reciprocal immunohistochemical profiles in oral carcinoma in situ

To evaluate differential expressions for keratin (K) subtypes 13 and 17 in oral borderline malignancies, we examined 67 surgical specimens of the oral mucosa for their immunohistochemical profiles. From those specimens, 173 foci of epithelial dysplasia, 152 foci of carcinoma in situ (CIS), and 82 foci of squamous cell carcinoma (SCC) were selected according to our diagnostic criteria, along with 20 areas of normal epithelia. In normal epithelia, there was no K17 positivity (0%), whereas definite K13 positivity (100%) was observed. The same tendencies were obtained in mild (undefined) and moderate (true) epithelial dysplasias (K17: 0%; K13: 100%). In contrast, all CIS (100%) had K17 positivities, while K13 positivities were lost in many of them (7%). Similar tendencies were confirmed in invasive SCC (K17: 100%, K13: 4%). Simultaneous immunopositivities for K17 and K13 were found only in SCC (7%) and CIS (4%) foci with distinct keratinization. These foci also showed K10 positivities, though K10 positive areas were not identical to K13 positive areas. The results indicate that expressions of K17 and K13 are reciprocal in oral epithelial lesions and that the K17 emergence is related to malignancies.

Enhanced Expression of Podoplanin in Oral Carcinomas in situ and Squamous Cell Carcinomas

Objective: Podoplanin, a known lymphatic endothelial cell marker, has been reported to be expressed in various types of cancer. To elucidate the expression of podoplanin in precancerous lesions, we examined the immunohistochemical profiles of podoplanin in oral squamous epithelial lesions. Method: We studied a total of 298 foci of squamous cell carcinoma (SCC), carcinoma in situ (CIS), epithelial dysplasia, and hyperplastic and/or normal epithelial lesions by immunohistochemistry using D2-40. Results: There was no positivity for podoplanin in normal or hyperplastic epithelia, while all of the CIS and SCC foci stained positive. Approximately one third of the mild dysplasia foci (10 of 36 foci, 28%) and 80% of moderate dysplasia foci (78/98) showed grade 1 positive reactions (positive only in the 1st layer). Grade 2 reactions (up to 4th layer) were seen in 4 of 98 moderate dysplasia foci (4%), 29 of 74 CIS foci (39%), and 3 of 30 SCC foci (10%). Grade 3 reactions (to more than 5th layer) were found in 35 (47%) CIS foci and 26 (87%) SCC foci. Conclusions: The relationship between the present histological categorization and podoplanin grade was statistically significant. D2-40 expression is considered to be related to the severity of oral precancerous lesions.

Nuclear translocation of β‐catenin synchronized with loss of E‐cadherin in oral epithelial dysplasia with a characteristic two‐phase appearance

Alvarado C G, Maruyama S, Cheng J, Ida‐Yonemochi H, Kobayashi T, Yamazaki M, Takagi R & Saku T u2028(2011) Histopathology59, 283–291

Combined immunohistochemistry for the differential diagnosis of cystic jaw lesions: its practical use in surgical pathology

Tsuneki M, Yamazaki M, Cheng J, Maruyama S, Kobayashi T & Saku Tu2028(2010) Histopathology57, 806–813

Podoplanin expression profiles characteristic of odontogenic tumor-specific tissue architectures

Podoplanin, a representative immunohistochemical marker for lymphatic endothelial cells, is also expressed in many other kinds of cancer cells, although its pathophysiological function is largely unknown. Our aim was to determine immunolocalization modes of podoplanin among odontogenic tumors to discuss possible roles of podoplanin in their characteristic tissue architecture formation. Immunohistochemical profiles of podoplanin were investigated in 40 surgical specimens from ameloblastoma (AM), adenomatoid odontogenic tumor (AOT), calcifying cystic odontogenic tumor (CCOT), and keratocystic odontogenic tumor (KCOT) in comparison with those of proliferating cell nuclear antigen (PCNA), integrin β1, fibronectin, and matrix metalloproteinase 9 (MMP-9). Podoplanin was localized in the basal cell layer or in the peripheral zone of AM foci. It was found in spindle-shaped tumor cells of AOT, in both the basal and polyhedral cells of CCOT, and in the basal and parabasal cells of KCOT linings. Podoplanin-positive (+) cells were located within areas of PCNA+ cells, and integrin β1 was localized in the cell membrane of podoplanin+ cells in the intercellular space where fibronectin and MMP-9 were deposited. In conclusion, podoplanin+ cells and areas in odontogenic tumors are in close associations with extracellular matrix signalings as well as cell proliferation.

Loss of keratin 13 in oral carcinoma in situ: a comparative study of protein and gene expression levels using paraffin sections.

Immunohistochemical loss of keratin (K)13 is one of the most valuable diagnostic criteria for discriminating carcinoma in situ (CIS) from non-malignancies in the oral mucosa while K13 is stably immunolocalized in the prickle cells of normal oral epithelium. To elucidate the molecular mechanism for the loss of K13, we compared the immunohistochemical profiles for K13 and K16 which is not expressed in normal epithelia, but instead enhanced in CIS, with their mRNA levels by in-situ hybridization in formalin-fixed paraffin sections prepared from 23 CIS cases of the tongue, which were surgically removed. Reverse transcriptase-PCR was also performed using RNA samples extracted from laser-microdissected epithelial fragments of the serial paraffin sections in seven of the cases. Although more enhanced expression levels for K16 were confirmed at both the protein and gene levels in CIS in these seven cases, the loss of K13 was associated with repressed mRNA levels in four cases, but not in the other three cases. The results suggest that the loss of K13 is partly due to its gene repression, but may also be due to some unknown post-translational events.

Parenchymal-stromal switching for extracellular matrix production on invasion of oral squamous cell carcinoma.

It is poorly understood which cell type, tumor cells, or stromal cells are responsible for the production of extracellular matrix molecules in the neoplastic stroma. We studied the expression of 4 extracellular matrix molecules at the protein and messenger RNA levels in monocellular and 2 kinds of coculture systems between human squamous cell carcinoma (ZK-1) and fibroblast (OF-1) cell lines, which may correspond to carcinoma in situ and squamous cell carcinoma, respectively. Squamous cell carcinoma and carcinoma in situ tissue sections were also investigated by immunohistochemistry and in situ hybridization for extracellular matrix. Immunohistochemically, perlecan and tenascin C were localized in carcinoma cells in carcinoma in situ, whereas they were in the stromal space in squamous cell carcinoma. In monocellular culture conditions, expression levels for perlecan, tenascin C, and laminin were more predominant in ZK-1 than in OF-1, although those for fibronectin were more enhanced in OF-1. However, these extracellular matrix expression levels of OF-1 were elevated, whereas those of ZK-1 dropped when they were in coculture conditions. The differences between ZK-1 and OF-1 were significantly more evident in direct contact (ZK-1/OF-1, 56%-22%) than in indirect contact (63%-39%). These results indicate that oral squamous cell carcinoma cells produce extracellular matrix in the absence of stromal fibroblasts (or in carcinoma in situ) and that they stop producing extracellular matrix in the presence of fibroblasts (or in squamous cell carcinoma). It is hence suggested that stromal fibroblasts after direct contact with invading squamous cell carcinoma cells are more responsible than squamous cell carcinoma cells for the formation of neoplastic stroma, whereas carcinoma in situ cells have to produce and deposit extracellular matrix by themselves to form intraepithelial microstromal spaces.

Podoplanin is a novel myoepithelial cell marker in pleomorphic adenoma and other salivary gland tumors with myoepithelial differentiation

The expression of podoplanin, one of the representative immunohistochemical markers for lymphatic endothelium, is upregulated in various kinds of cancers. Based on our previous studies, we have developed a hypothesis that podoplanin plays a role in cell adhesion via its association with extracellular matrix (ECM). Since salivary pleomorphic adenoma is histologically characterized by its ECM-enriched stroma, we firstly wanted to explore the expression modes of podoplanin in pleomorphic adenoma and related salivary tumors by immunohistochemistry. In normal salivary gland, podoplanin was specifically localized in myoepithelial cells, which were also positively labeled by antibodies against P63, of the intercalated duct as well as acini. In pleomorphic adenoma, podoplanin was colocalized with P63 and CD44 in basal cells of glandular structures as well as in stellate/spindle cells in myxochondroid matrices, where perlecan and hyaluronic acid were enriched. The expression of podoplanin was confirmed at both protein and mRNA levels in pleomorphic adenoma cell systems (SM-AP1 and SM-AP4) by using immunofluorescence, western blotting, and reverse transcription polymerase chain reaction. Podoplanin was localized on the cell border as well as in the external periphery of the cells. Moreover, podoplanin expression was also confirmed in tumor cells with myoepithelial differentiation in myoepithelioma and intraductal papilloma. The results indicate that podoplanin can be regarded as a novel myoepithelial marker in salivary gland tumors and suggest that podoplanin’s communication with ECM molecules is essential to phenotypic differentiation to myoepithelial cells.

Short telomeres in an oral precancerous lesion: Q‐FISH analysis of leukoplakia

OBJECTIVESnA precancerous condition is a lesion that, if left untreated, leads to cancer or can be induced to become malignant. In the oral region, leukoplakia is a lesion that has been regarded as precancerous. In cases of oral carcinoma, we have frequently noticed that a type of leukoplakia histologically demonstrating hyper-orthokeratosis and mild atypia (ortho-keratotic dysplasia; OKD) is often associated with carcinoma, either synchronously or metachronously. Therefore, we consider OKD-type leukoplakia to be a true precancerous lesion.nnnMATERIALS AND METHODSnIn an attempt to clarify the relationship between OKD as a precancerous condition in the oral mucosa and telomere length, we estimated telomere lengths in this type of leukoplakia using quantitative fluorescence in situ hybridization, and also quantified the frequency of anaphase-telophase bridges (ATBs) in comparison with squamous cell carcinoma in situ (CIS) and the background tissues of CIS and OKD.nnnRESULTSnOrtho-keratotic dysplasia was frequently associated with squamous cell carcinoma (45.0%) and showed significantly shorter telomeres than normal control epithelium, CIS, or the background of CIS or OKD. The frequency of ATBs was much higher in OKD than in control epithelium or CIS.nnnCONCLUSIONnOrtho-keratotic dysplasia appears to be frequently associated with carcinoma, chromosomal instability, and excessively shortened telomeres, not only in the lesion itself but also in the surrounding background. Therefore, when this type of leukoplakia is recognized in the oral region, strict follow-up for oral squamous cell carcinoma is necessary, focusing not only on the areas of leukoplakia, but also the surrounding background.

Ghost cell odontogenic carcinoma arising in the background of a benign calcifying cystic odontogenic tumor of the mandible

Ghost cell odontogenic carcinoma (GCOC) is a rare malignant variant of odontogenic tumor with ghost cells; only 29 cases are documented. Our patient was a 68-year-old man with a painless, well-defined, radiolucent swelling of the mandibular gingiva in the right incisor-to-molar region. It was diagnosed as a benign calcifying cystic odontogenic tumor (CCOT) on fenestration biopsy. Eighteen years later, he returned with swelling in the same area. The lesion was excised, diagnosed as GCOC, and considered a secondary malignant manifestation of the benign CCOT. No adjuvant chemotherapy or radiotherapy was administered, and his postoperative course was uneventful for 48 months, with no recurrence or distant metastasis. Among the 30 reported cases of GCOC, the mean age at diagnosis was 40.3 years, 22 (73%) involved the maxilla. Twelve (40%) were secondary malignant manifestations of benign CCOTs or dentinogenic ghost cell tumors. Five patients died of recurrence or distant metastasis.