Thrombosis in acute promyelocytic leukemia.

INTRODUCTION: Compared to bleeding, major thromboses are a less commonly encountered problem in acute promyelocytic leukemia (APL), and our knowledge about the epidemiology of major thromboses in APL stems mainly from individual case reports. The purpose of this study was to provide a better understanding of the epidemiology of APL-related thrombosis as a first step towards developing preventive strategies. MATERIALS AND METHODS: We report a rare case of catastrophic acute myocardial infarction in a patient with APL while she developed the all-trans retinoic acid (ATRA) syndrome. We describe the pathogenesis of APL-related thrombosis and review all previously reported cases of major thromboses in APL. RESULTS: We found 94 cases of major thromboses in patients with APL. Both genders were almost equally affected. More than 80% of events occurred before or during induction therapy with deep vein thrombosis/pulmonary embolism (DVT/PE), cardiac events, and cerebrovascular accidents (CVA) constituting more than 75% of all cases. Arterial events were slightly more common than venous events. Only 2 arterial events occurred after completion of induction therapy. Thrombosis was associated with life-threatening hemorrhage in about 15%, significant coagulative defects in about 50%, and ATRA syndrome in about 13% of cases. Cardiac thrombotic events, DVT/PE, and CVA were associated with ATRA syndrome in 24%, 4.5%, and 5% of cases, respectively (p=0.09). None of the observed trends and associations reached statistical significance. CONCLUSIONS: This review advances our understanding of the epidemiology of major thromboses in APL. With accumulation of more cases in the literature, some of our results may become statistically significant.

Merkel cell carcinoma: high recurrence rate despite aggressive treatment.

BACKGROUND: Merkel cell carcinoma (MCC) is a rare aggressive neuroendocrine cancer of the skin whose incidence has been increasing. The objective of the study was to evaluate current treatment modalities, including sentinel lymph node (SLN) biopsy and outcomes and identify prognostic factors in patients with MCC. METHODS: A retrospective chart review of patients with MCC. Clinical, pathologic, treatment characteristics, disease status, and survival were collected. All slides were reviewed by a single pathologist, and additional pathologic elements were evaluated for prognosis. RESULTS: Twenty-six patients were identified in the study period. All patients were Caucasian with an average age of 71.3 y. Twenty-one patients had tumors in sun-exposed locations, and 13 had a prior history of skin cancer. All nonmetastatic patients underwent wide excision. SLN biopsy was successful in 19 patients. The SLN was positive in 21% of patients. Radiation therapy was used in 13 patients. Average follow-up was 26 mo, and median survival was 29 mo. Recurrence occurred in eight patients: four locoregional, two distant, one combined, and one unknown. Recurrence occurred in five patients with stage I disease. Five patients with negative SLN later developed recurrence. The presence of metastasis to the nodes was significant for recurrence. No other pathologic factor was found to have prognostic significance. CONCLUSIONS: Despite aggressive surgical and radiation treatment, MCC has a high rate of locoregional recurrence, even in early stage disease. SNLB is useful for the staging and management of patients. Further research is needed to identify better prognostic markers.

Detailed molecular fingerprinting of four new anaplastic thyroid carcinoma cell lines and their use for verification of RhoB as a molecular therapeutic target.

CONTEXT: Anaplastic thyroid carcinoma (ATC) is a highly aggressive carcinoma in need of therapeutic options. One critical component of drug discovery is the availability of well-characterized cell lines for identification of molecular mechanisms related to tumor biology and drug responsiveness. Up to 42% of human thyroid cancer cell lines are redundant or not of correct tissue origin, and a comprehensive analysis is currently nonexistent. Mechanistically, RhoB has been identified as a novel molecular target for ATC therapy. OBJECTIVE: The aim was to develop four ATC cell lines detailing genetic, molecular, and phenotypic characteristics and to test five classes of drugs on the cell lines to determine whether they inhibited cell proliferation in a RhoB-dependent fashion. DESIGN: Four cell lines were derived from ATC tumors. Short tandem DNA repeat and mutational status of the originating tumors and cell lines were performed along with molecular and phenotypic characterizations. Compounds were tested for growth inhibition and ability to up-regulate RhoB. RESULTS: Cell line authenticity was confirmed by DNA short tandem repeat analysis. Each proved unique regarding expression of thyroid markers, oncogene status, amplified and deleted genes, and proliferative growth rates. FTI-277, GGTI-286, lovastatin, romidepsin, and UCN-01 up-regulated RhoB and inhibited cell proliferation in a dose-responsive fashion with only romidepsin and FTI-277 being RhoB dependent. CONCLUSIONS: Molecular descriptions of thyroid lines were matched to the originating tumors, setting a new standard for cell line characterization. Furthermore, suppressed RhoB is implicated as a molecular target for therapy against ATC because five classes of drugs up-regulate RhoB and inhibit growth dose-responsively.