Kijong Yi

MicroRNA Expression Signatures Associated With BRAF-Mutated Versus KRAS-Mutated Colorectal Cancers

AbstractBRAF and KRAS genes are known to play a similar role in the activation of RAS-RAF-MEK-ERK signaling pathway in colorectal tumorigenesis. However, BRAF-mutated colorectal cancers (CRCs) have distinct clinicopathologic characteristics different from those of the KRAS mutated ones as in comparison the BRAF-mutated CRCs are associated with a much worse prognosis for the afflicted patients. This study aimed to determine the different miRNA expression signatures associated with BRAF-mutated CRCs in comparison to KRAS-mutated ones, and to identify the specific miRNAs possibly mediating the aggressive phenotype of the BRAF-mutated CRCs.We screened 535 formalin-fixed paraffin-embedded CRC tissue samples for the BRAF V600E mutation, and selected 7 BRAF-mutated and 7 KRAS-mutated CRCs that were tumor size, stage, and microsatellite status-matched. Affymetrix GeneChip® miRNA 4.0 Array was used for detection of miRNA expression differences in the selected samples. We validated the array results by quantitative reverse transcription polymerase chain reaction (qRT-PCR) for selected miRNAs.A total of 10 differentially expressed (DE) miRNAs associated with BRAF-mutated CRCs were obtained, including miR-31-5p, miR-877-5p, miR-362-5p, and miR-425-3p. miR-31-5p showed the highest fold change (8.3-fold) among all of the miRNAs analyzed. From the analyses of GO biological processes, the DE-miRNAs were functionally relevant to cellular proliferation such as positive regulation of gene expression (P = 1.26 × 10−10), transcription (P = 9.70 × 10−10), and RNA metabolic process (P = 1.97 × 10−9). Bioinformatics analysis showed that the DE-miRNAs were significantly enriched in cancer-associated pathways including neutrophin signaling (P = 6.84 × 10−5), pathways in cancer (P = 0.0016), Wnt signaling (P = 0.0027), and MAPK signaling pathway (P = 0.0036).Our results suggest that the DE-miRNAs in BRAF-mutated CRCs in comparison to KRAS-mutated CRCs are implicated in the aggressive phenotype of the BRAF-mutated CRCs. Further experimental validation is required to confirm these results.

MEL-18 loss mediates estrogen receptor–α downregulation and hormone independence

The polycomb protein MEL-18 has been proposed as a tumor suppressor in breast cancer; however, its functional relevance to the hormonal regulation of breast cancer remains unknown. Here, we demonstrated that MEL-18 loss contributes to the hormone-independent phenotype of breast cancer by modulating hormone receptor expression. In multiple breast cancer cohorts, MEL-18 was markedly downregulated in triple-negative breast cancer (TNBC). MEL-18 expression positively correlated with the expression of luminal markers, including estrogen receptor-α (ER-α, encoded by ESR1). MEL-18 loss was also associated with poor response to antihormonal therapy in ER-α-positive breast cancer. Furthermore, whereas MEL-18 loss in luminal breast cancer cells resulted in the downregulation of expression and activity of ER-α and the progesterone receptor (PR), MEL-18 overexpression restored ER-α expression in TNBC. Consistently, in vivo xenograft experiments demonstrated that MEL-18 loss induces estrogen-independent growth and tamoxifen resistance in luminal breast cancer, and that MEL-18 overexpression confers tamoxifen sensitivity in TNBC. MEL-18 suppressed SUMOylation of the ESR1 transactivators p53 and SP1, thereby driving ESR1 transcription. MEL-18 facilitated the deSUMOylation process by inhibiting BMI-1/RING1B-mediated ubiquitin-proteasomal degradation of SUMO1/sentrin-specific protease 1 (SENP1). These findings demonstrate that MEL-18 is a SUMO-dependent regulator of hormone receptors and suggest MEL-18 expression as a marker for determining the antihormonal therapy response in patients with breast cancer.

Clinicopathological significance of dual-specificity protein phosphatase 4 expression in invasive ductal carcinoma of the breast.

Purpose Dual-specificity protein phosphatase 4 (DUSP4), also known as mitogen-activated protein kinase phosphatase (MKP) 2 is a member of the inducible nuclear MKP group. The role of DUSP4 in cancer development and progression appears to vary with the type of malignancy. The purpose of this study was to investigate DUSP4 expression in a case series of invasive ductal carcinoma of the breast. Methods We constructed tissue microarrays consisting of 16, 14, 47, and 266 cases of normal breast tissue, usual ductal hyperplasia, ductal carcinoma in situ, and invasive ductal carcinoma, respectively. DUSP4 expression was investigated by immunohistochemistry. Results Cytoplasmic DUSP4 expression was observed. DUSP4 was more frequently expressed in malignant than in benign cases (p=0.024). The mean DUSP4 expression score was significantly higher in malignant tumors than in benign lesions (p=0.019). DUSP4 expression was significantly correlated with a larger tumor size (>2 cm, p=0.015). There was no significant correlation between overall survival or disease-free survival and DUSP4 expression in all 266 patients. We evaluated the impact of DUSP4 expression on the survival of 120 patients with T1-stage tumors. Interestingly, Kaplan-Meier survival curves revealed that DUSP4 expression had a significant effect on both overall patient survival (p=0.034, log-rank test) and disease-free survival (p=0.045, log-rank test). In early T-stage breast cancer, DUSP4 expression was associated with a worse prognosis. Conclusion DUSP4 is frequently upregulated in breast malignancy, and may play an important role in cancer development and progression. In addition, it may be a marker of adverse prognosis, especially in patients with early T1-stage cancer.

Clinicopathological significance of CADM4 expression in invasive ductal carcinoma of the breast

Aims Cell adhesion molecule 4 (CADM4) is a novel tumour suppressor involved in cell adhesion. Loss or decreased expression of CADM4 has been associated with the development and progression of some cancers. The purpose of this study was to investigate the clinicopathological significance of CADM4 expression in breast cancer. Methods We constructed tissue microarrays to evaluate the immunohistochemical expression of CADM4 in 256 cases of invasive ductal carcinoma (IDC) and 45 cases of ductal carcinoma in situ (DCIS). Results CADM4 was expressed in 37 (82.2%) DCIS cases, and in 173 (67.6%) IDC cases. CADM4 expression was higher in DCIS than in IDC (p=0.049). Loss or decrease of CADM4 expression was significantly correlated with higher histological grade (p=0.020), absence of oestrogen receptors (p<0.001), absence of progesterone receptors (p=0.024), and overexpression of c-erbB-2 (p=0.018). In univariable and multivariable Cox regression analyses of all 256 IDC cases, CADM4 expression was not significantly associated with overall and disease-free survival. However, it showed a significant positive association with longer disease-free survival in 187 stages I and II IDC cases (p=0.039, log-rank test). Conclusions Loss or decrease of CADM4 expression seems to play an important role in breast cancer invasiveness, and it is associated with poorer biological parameters. CADM4 can be used as a novel marker predicting risk of recurrence and disease outcomes in stages I and II IDC.

Immunohistochemical Expression of Dual-Specificity Protein Phosphatase 4 in Patients with Colorectal Adenocarcinoma

The role of dual-specificity protein phosphatase 4 (DUSP4) appears to vary with the type of malignant tumors and is still controversial. The purpose of our study was to clarify the exact role of DUSP4 expression in colorectal adenocarcinoma. We constructed tissue microarrays and investigated DUSP4 expression by immunohistochemistry. DUSP4 was more frequently expressed in adenocarcinomas and lymph node/distant metastases compared to that in normal colorectal tissues and tubular adenomas (P < 0.001). Mean DUSP4 expression score was significantly higher in malignant tumors than in benign lesions (P < 0.001). DUSP4 expression was significantly correlated with older age (P = 0.017), male gender (P = 0.036), larger tumor size (P = 0.014), nonmucinous tumor type (P = 0.023), and higher T stage (P = 0.040). Kaplan-Meier survival curves revealed a significant effect of DUSP4 expression on both overall survival and disease-free survival in AJCC stage I (P = 0.008 and P = 0.003, resp., log-rank test) and male gender (P = 0.017 and P = 0.049, resp., log-rank test). DUSP4 protein is frequently upregulated in colorectal adenocarcinoma and may play an important role in carcinogenesis and cancer progression and may be a marker of adverse prognosis.

Dissecting the relationships of IgG subclasses and complements in membranous lupus nephritis and idiopathic membranous nephropathy

Membranous lupus nephritis (MLN) and idiopathic membranous nephropathy (IMN) are kidney diseases with similar morphology, but distinct etiologies, both producing glomeruli with immune deposits. Immunoglobulins and complements, the main components of the deposits, can be detected by immunofluorescence (IF) microscopy. Previous researches characterized the immune deposits only individually, but not the interactions between them. To study these relationships we analyzed an IF profile of IgG subclasses and complements (IgG1, IgG2, IgG3, IgG4, C3, C1q, and C4) in 53 and 95 cases of biopsy-confirmed MLNs and IMNs, respectively, mainly using information theory and Bayesian networks. We identified significant entropy differences between MLN and IMN for all markers except C3 and IgG1, but mutual information (a measure of mutual dependence) were not significantly different for all the pairs of markers. The entropy differences between MLN and IMN, therefore, were not attributable to the mutual information. These findings suggest that disease type directly and/or indirectly influences the glomerular deposits of most of IgG subclasses and complements, and that the interactions between any pair of the markers were similar between the two diseases. A Markov chain of IgG subclasses was derived from the mutual information about each pair of IgG subclass. Finally we developed an integrated disease model, consistent with the previous findings, describing the glomerular immune deposits of the IgG subclasses and complements based on a Bayesian network using the Markov chain of IgG subclasses as seed. The relationships between the markers were effectively explored by information theory and Bayesian network. Although deposits of IgG subclasses and complements depended on both disease type and the other markers, the interaction between the markers appears conserved, independent from the disease type. The disease model provided an integrated and intuitive representation of the relationships of the IgG subclasses and complements in MLN and IMN.

Diffuse Nodular Lymphoid Hyperplasia of the Intestine Caused by Common Variable Immunodeficiency and Refractory Giardiasis

Diffuse nodular lymphoid hyperplasia of the gastrointestinal tract is a rare disease characterized by numerous small polypoid nodules in the small intestine, large intestine, or both. It is associated with immunodeficiency and infection, such as Giardia lamblia and Helicobacter pylori. Although diffuse nodular lymphoid hyperplasia associated with common variable immunodeficiency (CVID) and giardiasis is already known, a few studies have reported a regression of the lymphoid nodules after the eradication of infection. We herein describe a case of diffuse nodular lymphoid hyperplasia of the intestine associated with CVID and refractory giardiasis that markedly improved after successfully treating giardiasis.

Clinicopathologic Correlations of E-cadherin and Prrx-1 Expression Loss in Hepatocellular Carcinoma.

Background Developing predictive markers for hepatocellular carcinoma (HCC) is important, because many patients experience recurrence and metastasis. Epithelial to mesenchymal transition (EMT) is a developmental process that plays an important role during embryogenesis and also during cancer metastasis. Paired-related homeobox protein 1 (Prrx-1) is an EMT inducer that has recently been introduced, and its prognostic significance in HCC is largely unknown. Methods Tissue microarray was constructed using surgically resected primary HCCs from 244 cases. Immunohistochemical staining of E-cadherin and Prrx-1 was performed. The correlation between E-cadherin loss and Prrx-1 expression, as well as other clinicopathologic factors, was evaluated. Results E-cadherin expression was decreased in 96 cases (39.4%). Loss of E-cadherin correlated with a higher recurrence rate (p < .001) but was not correlated with patient’s survival. Thirty-two cases (13.3%) showed at least focal nuclear Prrx-1 immunoreactivity while all non-neoplastic livers (n = 22) were negative. Prrx-1 expression was not associated with E-cadherin loss, survival or recurrence rates, pathologic factors, or the Ki-67 labeling index. Twenty tumors that were positive for E-cadherin and Prrx-1 had significantly higher nuclear grades than the rest of the cohort (p = .037). In Cox proportional hazard models, E-cadherin loss and large vessel invasion were independent prognostic factors for shorter disease-free survival. Cirrhosis and high Ki-67 index (> 40%) were independent prognostic factors for shorter overall survival. Conclusions Prrx-1 was expressed in small portions of HCCs but not in normal livers. Additional studies with a large number of Prrx-1-positive cases are required to confirm the results of this study.

Review of the touch preparation cytology of spindle epithelial tumor with thymus-like differentiation

We experienced a case of spindle epithelial tumor with thymus-like differentiation (SETTLE) with touch preparation cytology performed during the intraoperative frozen section diagnosis in a 22-year-old woman. The tumor was partially encapsulated by fibrous capsule. It was a highly cellular biphasic tumor characterized by fasciculated spindle cells with streaming pattern and tubulopapillary epithelial component. The tumor cells were positive for cytokeratin, vimentin, c-kit, epithelial membrane antigen (EMA), and thyroid transcription factor-1 (TTF-1). However, the tumor cells were negative for thyroglobulin, calcitonin, CD99, S-100 protein, CD34, smooth muscle actin, HBME-1, and galectin-3. The reviewed touch smears showed tight clusters with high cellularity. Most cellular clusters showed papillary configuration. However, some clusters showed spindle cells with streaming pattern. The spindle tumor cells showed elongated and cigar-shaped nuclei. Although the incidence is very rare, SETLLE should be included in the differential diagnosis when a spindle cell neoplasm is encountered in touch preparation cytology in young patients with a thyroid mass.

Lymphoepithelioma-like Carcinoma of the Renal Pelvis: A Case Report and Review of the Literature

Lymphoepithelioma is an undifferentiated epithelial tumor primarily described in the nasopharynx and characterized by syncytial nests of malignant epithelial cells with a prominent reactive lymphoid infiltrate [1]. A carcinoma that shows similar histological features but arises outside the nasopharynx is called lymphoepithelioma-like carcinoma (LELC). LELC has been described in a variety of organs including salivary glands, thymus, lungs, stomach, skin, uterine cervix, breast, prostate, and the urinary tract [2]. The renal pelvis is an extremely rare site for this tumor. To the best of our knowledge, only eight cases have been reported in the English literature and one case has been reported in the Korean literature [1-8]. We recently experienced a case of LELC arising in the right renal pelvis in a 65-year-old woman.