Prognostic Significance of EPHB2 Expression in Colorectal Cancer Progression

BACKGROUND: A receptor tyrosine kinase for ephrin ligands, EPHB2, is expressed in normal colorectal tissues and colorectal cancers (CRCs). The aim of this study was to investigate EPHB2 expression over CRC progression and determine its prognostic significance in CRC. METHODS: To measure EPHB2 mRNA and protein expression, real-time polymerase chain reaction and immunohistochemistry were performed in 32 fresh-frozen and 567 formalin-fixed paraffin-embedded CRC samples, respectively. We further investigated clinicopathological features and overall and recurrence-free survival according to EPHB2 protein expression. RESULTS: The EPHB2 level was upregulated in CRC samples compared to non-cancerous tissue in most samples and showed a strong positive correlation with AXIN2. Notably, CD44 had a positive association with both mRNA and protein levels of EPHB2. Immunohistochemical analysis revealed no difference in EPHB2 expression between adenoma and carcinoma areas. Although EPHB2 expression was slightly lower in invasive fronts compared to surface area (p < .05), there was no difference between superficial and metastatic areas. EPHB2 positivity was associated with lymphatic (p < .001) and venous (p = .001) invasion, TNM stage (p < .001), and microsatellite instability (p = .036). Kaplan–Meier analysis demonstrated that CRC patients with EPHB2 positivity showed better clinical outcomes in both overall (p = .049) and recurrence-free survival (p = .015). However, multivariate analysis failed to show that EPHB2 is an independent prognostic marker in CRCs (hazard ratio, 0.692; p = .692). CONCLUSIONS: Our results suggest that EPHB2 is overexpressed in a subset of CRCs and is a significant prognostic marker.

FOXO1 Suppression is a Determinant of Acquired Lapatinib-Resistance in HER2-Positive Gastric Cancer Cells Through MET Upregulation / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Lapatinib is a candidate drug for treatment of trastuzumab-resistant, human epidermal growth factor receptor 2 (HER2)–positive gastric cancer (GC). Unfortunately, lapatinib resistance renders this drug ineffective. The present study investigated the implication of forkhead box O1 (FOXO1) signaling in the acquired lapatinib resistance in HER2-positive GC cells. MATERIALS AND METHODS: Lapatinib-resistant GC cell lines (SNU-216 LR2-8) were generated in vitro by chronic exposure of lapatinib-sensitive, HER2-positive SNU-216 cells to lapatinib. SNU-216 LR cells with FOXO1 overexpression were generated by stable transfection of a constitutively active FOXO1 mutant (FOXO1A3). HER2 and MET in SNU-216 LR cells were downregulated using RNA interference. The sensitivity of GC cells to lapatinib and/or cisplatin was determined by crystal violet assay. In addition, Western blot analysis, luciferase reporter assay and reverse transcription–polymerase chain reaction were performed. RESULTS: SNU-216 LR cells showed upregulations of HER2 and MET, but downregulation of FOXO1 compared to parental SNU-216 cells. FOXO1 overexpression in SNU-216 LR cells significantly suppressed resistance to lapatinib and/or cisplatin. In addition, FOXO1 negatively controlled HER2 and MET at the transcriptional level and was negatively controlled by these molecules at the post-transcriptional level. A positive crosstalk was shown between HER2 and MET, each of which increased resistance to lapatinib and/or cisplatin. CONCLUSION: FOXO1 serves as an important linker between HER2 and MET signaling pathways through negative crosstalks and is a key regulator of the acquired lapatinib resistance in HER2-positive GC cells. These findings provide a rationale for establishing a novel treatment strategy to overcome lapatinib resistance in a subtype of GC patients.

Markers for Screening Lynch Syndrome Are Reliable and Useful for Identifying the Specimen Mislabeling

BACKGROUND: During specimen processing in surgical pathology laboratories, specimen-related adverse events (SRAEs), such as mislabeling and specimen mixed-up might occur. In these situations, molecular techniques using short tandem repeat (STR) loci are required to identify the personal identity. Microsatellite instability (MSI) test is widely used for screening the hereditary non-polyposis colon cancer (Lynch syndrome) in surgical pathologies using polymorphic STR markers. We tried to evaluate the applicability of the MSI test for SRAEs. METHODS: We obtained 253 MSI test results to analyze the allele frequencies. After calibrating the estimated nucleotide lengths, we calculated the allele frequencies, a random match probability, and a likelihood ratio (LR) of three dinucleotide STR markers (D5S349, D17S250, and D2S123). RESULTS: The distribution of LR was 136.38 to 5,606,213.10. There was no case of LR10,000. Furthermore, the combined probability of identity was 9.23x10(-4) and the combined power of exclusion was 0.99908. CONCLUSIONS: Using the three STR markers that are recommended for MSI test, all the cases were positively identified in 1% range and about one-third cases showed high LR (>10,000). These results showed that MSI tests are useful to screen the personal identity in case of SRAE in pathology laboratories.

Treatment Response and Long Term Follow-up Results of Nonspecific Interstitial Pneumonia

The purpose of this study was to investigate the long-term clinical course of non-specific interstitial pneumonia (NSIP) and to determine which factors are associated with a response to steroid therapy and relapse. Thirty-five patients with pathologically proven NSIP were included. Clinical, radiological, and laboratory data were reviewed retrospectively. The male-to-female ratio was 7:28 (median age, 52 yr). Thirty (86%) patients responded to steroid therapy, and the median follow-up was 55.2 months (range, 15.9-102.0 months). Five patients (14%) showed sustained disease progression and three died despite treatment. In the five with sustained disease progression, NSIP was associated with various systemic conditions, and the seropositivity of fluorescent antinuclear antibody was significantly associated with a poor response to steroids (P = 0.028). The rate of relapse was 25%, but all relapsed patients improved after re-treatment. The initial dose of steroids was significantly low in the relapse group (P = 0.020). In conclusion, progression is associated with various systemic conditions in patients who show progression. A low dose of initial steroids is significantly associated with relapse.

Expression of BamHI-A Rightward Transcripts in Epstein-Barr Virus-Associated Gastric Cancers / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: About 10% of all gastric cancers (GCs) are Epstein-Barr virus (EBV)-associated. However, the oncogene of EBV in gastric carcinogenesis has not yet been established. In the present study, we investigated the virus-derived transcripts in the EBV-infected GC cell line to explore the viral oncogene of EBV-positive GCs. MATERIALS AND METHODS: We used the SNU719 cell line, a naturally derived EBV-infected GC cell line. The individual expressed sequence tags from the cDNA libraries of SNU719 were searched against the mRNA subset extracted from the GenBank data base. Sequence reaction was carried out for the EBV-associated clones. Reverse transcription-polymerase chain reaction was performed after cells were partitioned into nuclear and cytoplasmic fractions. RESULTS: Using bioinformatic tools, we selected 13 EBV-associated clones from cDNA libraries of SNU719. By sequencing analysis, we revealed that they were all associated with RPMS1, one of the BamHI-A rightward transcripts (BART) of EBV. Some BART cDNAs such as RPMS1 and A73 are known to be translated into protein in vitro, and have been shown to have some biochemical functions relevant to tumorigenesis. But, presently, the BART transcripts were expressed only in the nucleus and not in the cytoplasm, arguing against their role as messenger RNAs. Some other BART transcripts expressed in GCs (BARF0, CST, vIL, BARF1, BLLF1, and BcLF1) were also extensively detected in the nucleus. CONCLUSION: BART transcripts are the predominant viral transcripts expressed in EBV-associated GCs, and they are located only in the nucleus. Therefore, it seems less likely that BART transcripts produce functional proteins to play a role in carcinogenesis of EBV-associated GCs.