BACKGROUND The ras family of proto-oncogenes encodes for small GTPases that play critical roles in cell-cycle progression and cellular transformation. ERK1/2 MAP kinases are major ras effectors. Tumors in chemically treated mouse skin contain mutations in the Ha-ras proto- oncogene. Amplification and mutation of Ha-ras has been shown to correlate with malignant progression of these tumors. Cell...

A human malignant fibrous histiocytoma cell line was established in vitro. Cells showed a wide variety of morphologies, although the karyotype study showed that the tumor was monoclonal in origin because of the presence of unique marker chromosomes in 100% of the cells examined (50 of 50). Cells were cloned according to their characteristic morphologies and biological behavior in culture. The c...

Perivascular epithelioid cell tumor of the lung, also known as clear cell "sugar" tumor, is a rare benign tumor arising from perivascular epithelioid cells. Herein, we present a case of spindle cell subtype of pulmonary perivascular epithelioid cell tumor with prominent calcification and malignant potential in a 49-year-old woman. Histologically, the striking feature of this lesion was attribut...

The spindle checkpoint that monitors kinetochore-microtubule attachment has been implicated in tumorigenesis; however, the relation between the spindle checkpoint and cell death remains obscure. In BUB1-deficient (but not MAD2-deficient) cells, conditions that activate the spindle checkpoint (i.e., cold shock or treatment with nocodazole, paclitaxel, or 17-AAG) induced DNA fragmentation during ...

Myofibroma is a rare benign spindle cell neoplasm in children that usually affects both soft tissue and bone in the head and neck region. Approximately one third of these cases are seen within jaw bones as solitary lesions. Solitary intra-osseous myofibroma of the jaw bone shares its clinical, radiographic and histological features with other spindle cell tumors. The rarity of this lesion can m...

Myoepithelial neoplasms of the soft tissues are a rare, heterogeneous group of tumors for which classification continues to evolve. While well defined within salivary glands, they can also arise in viscera and soft tissues, where diagnosis is challenging due to the lack of clinical and pathological familiarity. We present the case of a 36 year old man with myoepithelial carcinoma arising as a p...

Endoscopic ultrasound-guided fine-needle aspiration cytology (EUS-FNAC) has proven to be of significant value as a diagnostic method for the evaluation of esophageal mesenchymal tumors, such as true leiomyomas. Utilizing the cell block procedure, the present study reports the diagnostic approach of EUS-FNAC in two patients affected by this lesion, describing the cytological and immunocytochemic...

Malignant tumors of the ureter that display biphasic patterns are very rare; they include carcinosarcomas, sarcomatoid carcinomas and carcinomas with pseudosarcomatous stroma. Although the distinction between carcinosarcomas and sarcomatoid carcinomas has been extensively discussed in the past, the recent World Health Organization classification of urinary tract tumors (2004) does not distingui...

Eleven vialignant melanomas of the uveal tract have been studied by light and electron microscopy. Two types of cells were found in the epithelioid tumors: one, a darker type, contained large amounts of free RNP particles in single granules or in clusters, many smooth membranes and vesicles, and numerous mitochondria; the lighter type had similar cytoplasmic components, but in a lesser amount, ...

Solitary fibrous tumors (SFTs) are uncommon, with the pleura as a site of predilection. Central nervous system SFTs, particularly intracranial SFTs, are extremely rare. The lesions are generally benign and localized, and surgery is the main therapeutic solution. The current study reports the cases of a patient who presented with right haunch pain, right leg weakness and paresthesias for several...