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The patient was a 41-year-old woman, gravida 0. She had no notable medical history. Laparoscopic right salpingo-oophorectomy and left cystectomy were performed for bilateral ovarian endometriomas, which were both pathologically diagnosed as benign. Six months later, she presented with left lower abdominal pain and expressive aphasia. Examination revealed multiple cerebral infarctions and pulmonary embolism. The patient was diagnosed with Trousseau’s syndrome secondary to ovarian cancer, and anticoagulant therapy was initiated. Despite treatment, she developed visual field loss due to occlusion of the left retinal artery; dizziness due to cerebellar infarction and myocardial infarction; and right hemiplegia due to new cerebral infarction. She received chemotherapy (two courses of paclitaxel and carboplatin), which did not improve her condition, and died two months after onset. An autopsy revealed that her left ovary was enlarged to a size of 12 cm and an endometrioid carcinoma G2 was identified. Ovarian cancer had spread throughout the abdominal cavity, and a large amount of pleural and ascites fluid was present. Multiple thrombi were found in bilateral pulmonary arteries and bilateral common iliac veins. There was a 2.5 cm thrombus in the left ventricle apex, and the anterior descending branch was obstructed by thrombus with recanalization.

Cytokine-dependent cell lines have been used to analyze the cytokine-induced cellular signaling and the mechanism of oncogenesis. In the current study, we analyzed MOTN-1 and PLT-2 cell lines established from different stages of a T-cell large granular lymphocyte leukemia patient (Daibata et al. 2004). MOTN-1 is IL-2-dependent derived from the chronic phase, whereas IL-2-independent PLT-2 is from the aggressive and terminal stage. They shared considerable chromosome abnormalities and the pattern of T-cell receptor rearrangement, presuming that the cytokine independence of PLT-2 was due to the additive genetic abnormality. Besides IL-2, IL-15 supported MOTN-1 cell growth, because these receptors share b- and g-subunits. IL-2 activated ERK, AKT and STAT pathway of MOTN-1. STAT3 pathway of PLT-2 was also activated by IL-2, suggesting intact IL-2 induces signal transduction of PLT-2. However, ERK1/2 but not AKT, was continuously activated in PLT-2, consistent with the increased Ras-activity of PLT-2. Sequence analysis revealed KRAS G12A mutation but not NRAS and HRAS mutation of PLT-2 but not MOTN-1. Another signaling molecule affecting Ras-signaling pathway, SHP2, which has been frequently mutated in juvenile myelomonocytic leukemia (JMML), did not show mutation. Moreover, MEK inhibitor, PD98059, as well as farnesylation inhibitor inhibited PLT-2 cell growth. Using NIH3T3 and MOTN-1, ERK activation, increased cell proliferation and survival by KRAS G12A were shown, suggesting the important role of KRAS G12A in IL-2-independent growth of PLT-2. Taken together, KRAS G12A is important for IL-2-independent growth of PLT-2 cells and suggests the possibility of involvement of KRAS mutation with disease progression.