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Selected Abstracts

Immunohistochemical evidence of PTEN in oral squamous cell carcinoma and its correlation with the histological malignancy grading system

JOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 7 2002
Cristiane Helena Squarize
Abstract PTEN is a tumor suppressor gene that encodes a dual phosphatase protein capable of modulating membrane receptors and interaction of the cell and extracellular stimuli. PTEN regulates cell physiology such as division, differentiation/apoptosis and also migration and adhesion. The expression of PTEN was evaluated by immunohistochemistry in OSCC and compared to a well-established histological malignancy grading system. The well-differentiated OSCC were 59.1% and poorly differentiated were 40.9%. According to PTEN expression, the cases were 45.5% positive (the entire tumor showed stained), 22.7% mixed (both negative and positive cells were present) and 31.8% negative (no staining was seen in the tumor cells). PTEN expression in OSCC was related to the malignancy grade (P < 0.0005). Aggressive tumors with a high score of malignancy did not express PTEN, and clearly, the PTEN expression was present in the epithelium adjacent to the tumor. Negative cells were in the invasion border of the tumor. This result suggests that PTEN is related to histologic pattern and biological behavior of OSCC and may be a used as a prognostic marker in the future. The role of PTEN during carcinogenesis and as a biomarker should be further investigated. [source]

Preoperative radiation therapy with selective dose escalation to the margin at risk for retroperitoneal sarcoma

CANCER, Issue 2 2006
Ching-Wei D. Tzeng MD
Abstract BACKGROUND Retroperitoneal sarcomas (RPSs) are rare tumors with poor survival rates due to difficult resectability and high local and distant recurrence rates. Preoperative radiation therapy appears to have dosimetric advantages to utilize the tumor as a tissue expander to limit exposure of small bowel to higher radiation doses. METHODS Between June 1999 and December 2003, 16 consecutive patients with biopsy-proven RPS were treated with preoperative radiation with selective dose escalation. This included 45 grays (Gy) in 25 fractions to the entire tumor plus margin and a boost dose of 57.5 Gy to the volume predicted as high risk for positive surgical margins. Treatment toxicity and local control were evaluated prospectively as primary endpoints. The secondary goal was the theoretical calculation of future dose escalation and feasibility. Each patient underwent laparotomy. Tumor response was judged using computed tomography (CT) scan and by necrosis on final pathology. Theoretical treatment plans evaluated the potential for additional radiation dose escalation. RESULTS All patients completed the radiation protocol. The most common acute side effects were nausea/vomiting, which affected 4 patients (25%), with only 1 patient requiring inpatient intravenous hydration. There was no severe late postoperative morbidity or mortality. Twelve tumors (75%) decreased in maximum dimension, with a median decrease of 9.4%. Fourteen of 16 patients (88%) underwent complete macroscopic resection. With a median follow-up of 28 months (range, 7-52 months), there were only 2 local recurrences. The actuarial 2-year local control rate was 80%. Theoretical treatment plans suggest that significant dose escalation (up to 80 Gy) may be possible. CONCLUSIONS Preoperative radiation therapy with selective dose escalation to the margin at risk is tolerable and allows higher radiation dose to the volume judged to be at greatest risk for local tumor recurrence. Cancer 2006. © 2006 American Cancer Society. [source]

Angiographic subsegmentectomy for the treatment of patients with small hepatocellular carcinoma

CANCER, Issue 4 2003
Shozo Iwamoto M.D.
Abstract BACKGROUND The therapeutic results of nonsurgical treatment for patients with hepatocellular carcinoma (HCC) have been poor, and improved treatments are needed. The authors recently developed a new technique called angiographic subsegmentectomy for the treatment of patients with small HCC. METHODS The technique includes confirming the diagnosis of small HCC using a helical computed tomography (CT) scan combined with an angiography system for identifying the tumor-feeding subsegmental hepatic artery, injecting lipiodol containing farmorubicin until it enters the portal vein in sufficient amounts, and injecting sponge particles into the hepatic artery for embolization. Occlusion of the hepatic artery with gel particles and occlusion of the portal vein by lipiodol induce infarction necrosis, which encompasses the entire tumor and the surrounding liver parenchyma. RESULTS The treatment was given to 23 patients with 30 HCC tumors that measured < 20 mm in greatest dimension. It was successful in all 23 patients. Serum alanine aminotransferase levels were elevated to a significant level in the majority of patients after treatment, mild ascites developed in three patients, and the patients complained of pain and fever posttreatment that were controlled readily. No patients developed hepatic failure. Only one patient developed recurrent disease posttreatment at 1.5 years, for a recurrence rate of 5% at 1 year and 6.6% at 1.5 years, a rate that has never been achieved with other treatment modalities. CONCLUSIONS Angiographic subsegmentectomy is a novel treatment for patients with small HCC. The results indicated that it is equivalent to undergoing small resection and is superior to conventional arterial chemoembolization. Cancer 2003;97:1051,6. © 2003 American Cancer Society. DOI 10.1002/cncr.11106 [source]

Significance of nitroimidazole compounds and hypoxia-inducible factor-1 for imaging tumor hypoxia

CANCER SCIENCE, Issue 8 2009
Shinae Kizaka-Kondoh
A tumor-specific microenvironment is characterized by hypoxia, in which oxygen tension is considerably lower than in normal tissues. The hypoxic status of various solid tumors has been attributed as an indicator of adverse prognosis due to tumor progression toward a more malignant phenotype with increased metastatic potential and resistance to treatment. Various exogenous and endogenous markers for hypoxia are currently available and studied in relation to each other, tumor architecture, and tumor microenvironment. Over the last few decades, various methods have been suggested to assess the level of oxygenation in solid tumors. Among them, nitroimidazole compounds have provided promising information on tumor hypoxia. To quantify the extent of hypoxia requires that nitroimidazole binding be primarily dependent on oxygen concentration as well as nitroreductase levels in the tumor cells. Furthermore, recent progress in molecular biology has highlighted a transcription factor, hypoxia-inducible factor (HIF)-1, whose activity is induced by hypoxia. HIF-1 plays a central role in malignant progression by inducing the expression of various genes, whose functions are strongly associated with malignant alteration of the entire tumor. The cellular changes induced by HIF-1 are extremely important therapeutic targets of cancer therapy, particularly in the therapy against refractory cancers. In this review, we will discuss the significance of pimonidazole and HIF-1 as exogenous and endogenous hypoxia markers, respectively, as well as their evaluation and imaging of tumor hypoxia. (Cancer Sci 2009) [source]