This paper investigates the differences in college learners' perceptions and correlations of factors related to willingness to communicate (WTC) in an English mediated instruction (EMI) class. Based on a survey of 50 collegiates (33 males, 17 females) and two rounds of interviews with 15 students, the t-tests showed that there were not many statistical differences depending on learner characteristics except the learners' grade difference affecting their perception of improvement in English. However, depending on the course types, the Kruskal-Wallis test showed statistically significant differences in the categories of present level of participation, expected level of participation with L1 option, question & answer, group collaboration, active listening, and preference to EMI with L1 option. Furthermore, the factors of WTC appeared strongly correlated with their perceptions on the improvement in English, increased confidence, and the extent of learning in the EMI class. According to qualitative analyses of open-ended questions in the survey and interviews, the learners thought group presentations in English were most difficult. They also responded that their low English proficiency, peer pressure, and the student-orientedness in class made them passive and less confident. The learners, however, adopted diverse coping strategies to overcome such difficulties. They were also positive about the limited use of L1 in the EMI class. Implications for EMI are suggested.

Human natural killer (NK) cells are major players in innate immune response. The functions of these cells as a scavenger of cancer cells are enhanced by cytokines such as interleukin-2 (IL-2), which play an important role in immune response in both tumors and virally infected cells. Liver cancer has a high incidence rate and is a major cause of death in Korea. We provide evidence that human NK cells inhibit tumor growth of the hepatocellular carcinoma cell line SNU-354. NK cells were cultured with human IL-2 for 14 days, yielding an enriched NK cell population containing 35% CD8+ cells, 6% CD4+ cells, and 51% CD16+ /CD56+ cells. Intravenous injection of NK cells at doses from 2.5 to 10 million cells/mouse was administered once per week in a nude mouse model that retains human liver tumor induced by implantation of SNU-354 cells. The results showed that human NK cells were recruited within tumor tissue and inhibited SNU-354 tumor growth by 32%, 58%, and 65%. The current data suggest the potential for use of NK cell-based immunotherapy for treatment of human liver cancer.