Nam Hoon Cho

CD24+ cells from hierarchically organized ovarian cancer are enriched in cancer stem cells

Cancer stem cells (CSCs) have been identified in solid tumors and cancer cell lines. In this study, we isolated a series of cancer cell clones, which were heterogeneous in growth rate, cell cycle distribution and expression profile of genes and proteins, from ovarian tumor specimens of a patient and identified a sub-population enriched for ovarian CSCs defined by CD24 phenotype. Experiments in vitro demonstrated CD24+ sub-population possessed stem cell-like characteristics of remaining quiescence and more chemoresistant compared with CD24− fraction, as well as a specific capacity for self-renewal and differentiation. In addition, injection of 5 × 103 CD24+ cells was able to form tumor xenografts in nude mice, whereas equal number of CD24− cells remained nontumorigenic. We also found that CD24+ cells expressed higher mRNA levels of some ‘stemness’ genes, including Nestin, β-catenin, Bmi-1, Oct4, Oct3/4, Notch1 and Notch4 which were involved in modulating many functions of stem cells, and lower E-cadherin mRNA level than CD24− cells. Altogether, these observations suggest human ovarian tumor cells are organized as a hierarchy and CD24 demarcates an ovarian cancer-initiating cell population. These findings will have important clinical applications for developing effective therapeutic strategies to treat ovarian cancer.

HPV integration begins in the tonsillar crypt and leads to the alteration of p16, EGFR and c-myc during tumor formation

The prevalence of human papillomavirus (HPV) infection is high in the oropharyngeal mucosal regions, of which the tonsil is the most commonly affected. There may be a link between HPV and the pathogenesis of tonsillar cancer (TC), because of common anatomical characteristics between cervical and tonsillar cancer. We aimed to clarify whether HPV directly affects the oncogenesis and biologic behavior of TC by making a comparison between infection prevalence, physical status and viral loading numbers, and clinicopathologic prognostic factors. To compare HPV‐related molecules between TC and tonsillitis (CFT), p16, survivin, HIF‐1α, skp‐1, cyclin A, cyclin B1, c‐myc and EGFR were investigated. We observed a significant difference in HPV prevalence between 52 TCs and 69 CFTs (73.1% vs. 11.6%), and most of the HPVs were type 16 (87.2%) and nonepisomal (94.1%). Most TCs associated with HPV arose from the tonsillar crypts, and tended to be inverted and poorly differentiated. Compared with HPV‐negative TC, HPV‐positive TC showed a strong association with p16 overexpression (p < 0.0001), and an inverse association with EGFR amplification (p = 0.0478). HPV‐16 integration status was strongly associated with c‐myc amplification (p = 0.034) and HIF‐1α overexpression (p = 0.022). HPV‐16 integration could be directly related to tonsillar carcinogenesis initially in tonsillar crypts, followed by cell cycle aberration such as p16 overexpression related to the G1‐S phase.

Synchronous Coexpression of Epidermal Growth Factor Receptor and Cyclooxygenase-2 in Carcinomas of the Uterine Cervix A Potential Predictor of Poor Survival

Purpose: To evaluate the potential of the new prognostic information gained by analyzing the coexpression of epidermal growth factor receptor (EGFR) and cyclooxygenase-2 (COX-2) in cervical cancer patients. Experimental Design: Sixty-eight patients with International Federation of Gynecology and Obstetrics stage IIB squamous cell carcinoma of the uterine cervix, who underwent concurrent chemoradiotherapy between 1993 and 1996, were divided into the following four groups according to their immunoreactivities for EGFR and COX-2 in paraffin-embedded sections: (a) the EGFR-negative/COX-2-negative group (n = 11); (b) the EGFR-negative/COX-2-positive group (n = 8); (c) the EGFR-positive/COX-2-negative group (n = 27); and (d) the EGFR-positive/COX-2-positive group (n = 22). The clinical features, patterns of treatment failure, and survival data in the four groups were compared. Results: Positive immunoreactivity for EGFR and COX-2 was observed in 49 of 68 (72%) and 19 of 68 (28%), respectively. However, no strong correlation was found between the levels of EGFR and COX-2 immunopositivity (R2 = 0.05, P = 0.07). Patients in the EGFR-positive/COX-2-positive group had a higher likelihood of locoregional recurrence than those in the other three groups (P = 0.02). Of the patients in the four groups, patients positive for both oncoproteins were found to have the worst prognosis with an overall 5-year disease-free survival rate of 55% compared with 91% for the EGFR-negative/COX-2-negative patients, 88% for the EGFR-negative/COX-2-positive patients, and 69% for the EGFR-positive/COX-2-negative patients (P = 0.05, log-rank test). In addition, the synchronous coexpression of the EGFR and COX-2 oncoproteins was found to be an independent prognostic factor by univariate and multivariate analyses (relative risk = 4.0, P = 0.03). Conclusions: Given these observations, we conclude that the coexpression of EGFR and COX-2 immunoreactivity may be used as a potent molecular risk factor for predicting the poor survival of patients with the International Federation of Gynecology and Obstetrics stage IIB squamous cell carcinoma of the uterine cervix.

Surgical Anatomy of the Sphenopalatine Artery in Lateral Nasal Wall

Objective We investigated the surgical anatomy of the sphenopalatine artery. First, the location of the sphenopalatine foramen on the lateral nasal wall and the pattern of the main branches of the sphenopalatine artery from the sphenopalatine artery were studied. Second, the course of the posterior lateral nasal artery with respect to the posterior wall of the maxillary sinus, the perpendicular plate of the palatine bone, and the pattern of distribution of its branches on the fontanelle was determined. Third, the distribution pattern on the inferior turbinate was analyzed.

Genotyping of 22 human papillomavirus types by DNA chip in Korean women: Comparison with cytologic diagnosis

OBJECTIVE More sensitive and reliable methods than individual testing (such as polymerase chain reaction, restriction fragment length polymorphism, and Southern blot) should be developed as screening tools for the detection of latent human papillomavirus. Today, the new Bethesda system recommends human papillomavirus testing as an adjuvant to the conventional Papanicolaou smear for more comprehensive identification of women at certain risk of cervical neoplasia. We performed human papillomavirus genotyping with the newly designed human papillomavirus DNA chip, which is based on polymerase chain reaction for high-throughput screening power, and compared the results with the results of a Papanicolaou smear according to the new Bethesda system. STUDY DESIGN Polymerase chain reaction amplifications of the human papillomavirus L1 region from biologic samples were hybridized to silanized glass slides by a microarrayer, which comprised 22 specific oligonucleotide probes to their genotypes, consisting of 15 high-risk and 7 low-risk types. Two cervical cancer cell lines and 20 plasmids that contained each type of the human papillomavirus whole genome were used for the evaluation of this method; in all cases, the cancer cell lines and plasmids showed clear positive signals on their corresponding positions. A comparative study that used 685 cervicovaginal swabs was performed by human papillomavirus DNA chip microarray together with Papanicolaou diagnosis. RESULTS Human papillomavirus was identified as positive in 31.9% of the 414 control samples and in 78.6% of the 271 neoplastic lesions. The major prevailing human papillomavirus genotypes were human papillomavirus types 16, 58, and 18, in descending order of incidence (average overall, 78.8%). Almost all of the remaining cases were comprised of human papillomavirus types 39, 52, 56, and 51. The frequency of multiple infection of human papillomavirus was highest in low-grade squamous intraepithelial lesion but was lowest in squamous cell carcinoma. All cases that exhibited infection of single human papillomavirus type 58 were squamous cell carcinoma. CONCLUSION Human papillomavirus types 16, 18, and 58 were confirmed to be major causative factors for cervical carcinogenesis. Low-grade squamous intraepithelial lesion is a heterogeneous entity that is composed of different human papillomavirus subtypes and prevails in younger women (<40 years old). The human papillomavirus chip has potential use as a high-throughput screening test.

Stromal fibroblasts from the interface zone of human breast carcinomas induce an epithelial–mesenchymal transition-like state in breast cancer cells in vitro

Fibroblasts were extracted from tissue in tumor burden zones, distal normal zones and interface zones between tumor and normal tissue of human breast carcinomas, and the corresponding fibroblasts were designated as cancer-associated fibroblasts (CAFs), normal zone fibroblasts (NFs) and interface zone fibroblasts (INFs). The crosstalk between three types of fibroblasts and breast cancer cells was evaluated using an in vitro direct co-culture model. We found that INFs grew faster and expressed higher levels of fibroblast activation protein than did NFs and CAFs. Compared with CAFs and NFs, INFs grown with breast cancer cells were significantly more effective in inducing an epithelial-mesenchymal transition (EMT) in cancer cells, as indicated by induction of vimentin and N-cadherin and downregulation of E-cadherin. This EMT process was also accompanied by activation of extracellular signal-regulated kinase (ERK) and modulation of membrane-type 1 matrix metalloproteinase (MT1-MMP) expression. Additionally, INFs promoted breast cell migration to a larger extent compared with NFs and CAFs. Taken together, these findings indicate that INFs isolated from the tumor interface zone exhibited more robust biological modulatory activity than did NFs and CAFs isolated from normal and tumor zones of the same tumor tissue, suggesting that the interface zone of the tumor represents a dynamic region vital to tumor progression.

Molecular proteomics imaging of tumor interfaces by mass spectrometry

The specific molecular profiles of ovarian cancer interface zones (IZ), the region between tumors and normal tissues, were evaluated using a new method involving matrix-assisted laser desorption/ionization (MALDI)-imaging mass spectrometry (IMS). We analyzed three ovarian serous carcinomas using MALDI-IMS. Principal component analysis (PCA) was used to evaluate the quality of tissue spatial features based on MALDI-IMS, and for analysis of large data sets of MALDI-IMS. Two-dimensional gel electrophoresis and fluorescence microscopy were used to verify interface-specific proteins. Unique profiles were identified for the tumors, the normal zone, and the IZ. Through MALDI analysis, two interface-specific proteins, plastin 2 and peroxiredoxin 1 (PRDX 1), were identified as differentially regulated between zones. Fluorescence microscopy revealed high expression levels of plastin 2 and PRDX 1 along the IZ of ovarian tumors. This comparative proteomics study using tissue MALDI-IMS suggested that the IZ is different from the adjacent tumor and normal zones, and that plastin 2 and PRDX 1 may be interface markers specific to ovarian tumors.

Prevalence of erectile dysfunction in Korean men with Type 2 diabetes mellitus.

Aims  We investigated the prevalence and risk factors for developing erectile dysfunction (ED) in 1312 Korean men with diabetes in a multicentre study.

Extramammary Paget's disease of penis and scrotum.

OBJECTIVES To make clear the uncertainty of the clinical outcome of extramammary Pagets disease (EMPD). Penile and scrotal involvement of EMPD is exceedingly rare, and only small series or case reports have been reported. METHODS From 1995 to 2003, 36 patients with penile and scrotal EMPD were treated and followed up. Local wide excision was done in all patients with or without intraoperative frozen biopsy analysis. RESULTS Of the 36 patients, 13 (36.1%) underwent intraoperative frozen biopsy analysis and only 1 patient (7.7%) had a positive surgical margin. However, 23 (63.9%) underwent local wide excision with excessive surgical margins of up to 1 to 2 cm only by gross examination, but 17 (73.9%) of them had positive surgical margins (P <0.01). Of the 17 patients with positive surgical margins, 8 developed local recurrence at a median of 8 months of follow-up (P <0.05). One patient who had invasion to the subcutaneous tissue died of metastatic EMPD and internal malignancy (renal cell carcinoma) at 17 months after the initial operation. No patient had underlying adnexal carcinoma. CONCLUSIONS The results of our study indicate that local wide excision with intraoperative frozen biopsy analysis is essential to the complete treatment of EMPD.

Plasmacytoid transitional cell carcinoma of urinary bladder: A clinicopathologic study of 9 cases

In this report, we summarized the clinicopathologic features of 9 cases of plasmacytoid transitional cell carcinoma (TCC) of the urinary bladder, a rare variant of TCC. All 9 patients were men with a mean of age 64.3 years (range, 46 to 81 y). All but 1 patient presented with gross hematuria; the remaining patient had urgency and microscopic hematuria. Cystoscopic findings revealed a dominant solid mass with surrounding multiple papillary lesions in 6 cases and multiple masslike lesions in 3 other cases. The initial diagnosis of plasmacytoid TCC was made on transurethral resection in 8 cases and cystoscopic biopsy in 1. One patient had TNM stage I disease, 2 had stage II disease, 3 had stage III disease, and 3 had stage IV disease. Four patients were treated by radical cystectomy with chemotherapy, 2 by radical cystectomy alone, 1 each by chemotherapy or intravesical bacillus Calmette-Guerin infusion alone, and 1 did not receive any further therapy. Microscopically, all tumors contained plasmacytoid cells, which composed 30% to 100% of the entire tumor. Eight of 9 cases were associated with high-grade TCC, and transitional cell carcinoma in situ was present in 4 cases. The plasmacytoid tumor cells were characterized by eccentrically located nuclei and abundant eosinophilic cytoplasm. Interestingly, plasmacytoid transitional cell carcinoma in situ was noted in 1 case. Immunohistochemical staining demonstrated that both plasmacytoid and conventional TCC components were positive for cytokeratins 7 and 20. The mean Ki-67 labeling index was 30% (range, 10% to 50%), and p53 expression in the majority of cases was low (5% to 10%), except for in 2 cases (70% and 80%). The mean follow-up in 8 patients was 24.5 months (range, 5 to 47 mo); the other patient was lost to follow-up. Five patients died of disease from 5 to 36 months, 2 patients were alive with disease at 30 and 47 months, and 1 patient was alive and well at 36 months with no evidence of disease. In summary, plasmacytoid TCC tends to present at an advanced stage and to have a poor prognosis. Morphologic recognition and distinction from other plasmacytoid malignant neoplasms is critical for its clinical management and immunohistochemical studies may be required for differential diagnosis.