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Piotr Kulesza

Publications and source records attributed to Piotr Kulesza.

8 recordsLinked to original sources
PubMed2006

An in vivo platform for translational drug development in pancreatic cancer.

Effective development of targeted anticancer agents includes the definition of the optimal biological dose and biomarkers of drug activity. Currently available preclinical models are not optimal to this end. We aimed at generating a model for translational drug development using pancreatic cancer as a prototype. Resected pancreatic cancers from 14 patients were xenografted and expanded in successive groups of nude mice to develop cohorts of tumor-bearing mice suitable for drug therapy in simulated early clinical trials. The xenografted tumors maintain their fundamental genotypic features despite serial passages and recapitulate the genetic heterogeneity of pancreatic cancer. The in vivo platform is useful for integrating drug screening with biomarker discovery. Passages of tumors in successive cohorts of mice do not change their susceptibility to anticancer agents and represent a perpetual live bank, facilitating the application of new technologies that will result in the creation of an integrated stable database of tumor-drug response data and biomarkers.

Animals↗
PubMed2006

Immunohistochemical and genetic evaluation of deoxycytidine kinase in pancreatic cancer: relationship to molecular mechanisms of gemcitabine resistance and survival.

Gemcitabine is considered the standard first-line therapy for patients with advanced pancreatic cancer. More recent strategies have focused on improving the efficacy of gemcitabine by either improving the method of delivery or by combining gemcitabine with other non-cross-resistant chemotherapy agents or with small-molecule drugs. However, the clinical benefits, response rates, and duration of responses have been modest. Deoxycytidine kinase (dCK) is the rate-limiting enzyme involved in the metabolism of gemcitabine. The expression of dCK has been postulated to be correlative of gemcitabine resistance. We determined the relationship of dCK immunohistochemical protein expression and/or genetic status of dCK in a panel of human pancreatic cancer tissues and pancreatic cancer cell lines and determined the relationship of these variables to the clinical outcome of patients treated with gemcitabine. We report that dCK protein expression is expressed in the majority of pancreatic cancers analyzed (40 of 44 cases, 91%) and showed a range of labeling intensities ranging from 1+ (labeling weaker in intensity than normal lymphocytes present in same section) to 3+ (labeling greater in intensity than normal lymphocytes present in same section). When labeling intensity was compared with survival, low dCK expression (1+ labeling) was correlated with both overall survival (P < 0.009) and progression-free survival following gemcitabine treatment (P < 0.04). Low dCK labeling intensity was also significantly correlated with patient age (70.3 +/- 8.1 versus 59.8 +/- 7.4 years; P < 0.0006), suggesting that age-related methylation of the dCK gene may account in part for the observed differences. Sequencing of the entire dCK coding sequence in 17 cell lines and 9 patients' cancer tissues with disease progression while on gemcitabine did not identify any mutations, suggesting that genetic alterations of dCK are not a common mechanism of resistance to gemcitabine for this tumor type. Moreover, dCK labeling showed similar patterns and intensities of labeling among matched pretreatment and post-treatment tissues. In summary, pretreatment levels of dCK protein are most correlated with overall survival following gemcitabine treatment and are stable even after resistance to gemcitabine is clinically documented.

Antimetabolites, Antineoplastic↗
PubMed2005

Rhabdoid meningioma occurring in an unrelated resection cavity with leptomeningeal carcinomatosis. Case report.

Rhabdoid meningioma (RM) is a recently described, aggressive variant of meningioma. The authors report a case of RM occurring in the resection cavity of an unrelated neurosurgical procedure, temporal lobectomy for intractable seizures. The patient presented with intractable headache 10 years after the temporal lobectomy. Imaging revealed a dura-based, uniformly enhancing lesion within the resection cavity. She underwent gross-total resection and the findings of the surgical pathological report were consistent with an RM, with a dramatically elevated MIB-1 index of approximately 50%. The patient's clinical course was complicated by severe pain and communicating hydrocephalus secondary to rapid dissemination of malignant cells throughout the CSF pathways. Despite aggressive measures, including tumor resection, ventriculoperitoneal shunt placement, and the initiation of conventional radiation therapy, the ensuing leptomeningeal carcinomatosis proved to be rapidly fatal.

Adult↗
PubMed2004

Cytopathologic grading of hepatocellular carcinoma on fine-needle aspiration.

BACKGROUND: Hepatocellular carcinoma (HCC) is routinely graded histopathologically using a modified Edmondson system (ES). The cytologic grading of HCC has been used predominantly as an adjunct in differential diagnoses (i.e., to help distinguish HCC from other tumors as well as nonneoplastic lesions). However, there are unanswered questions regarding the reliability of the cytologic grading of HCC and its correlation with histologic follow-up. METHODS: A total of 106 cases of HCC were identified in the authors' cytopathology files from 1977 to the present. Of these cases, 64 had either a core needle or excisional biopsy sample that was judged to be adequate for histologic grading. From each case smears were graded independently in a blinded fashion by two cytopathologists, and tissue slides were graded by a liver pathologist. The cytopathologists' grading was then adjudicated by considering the histologic diagnosis as the "truth standard". Finally, after the scores were calculated, a statistical analysis was performed to ascertain the accuracy of the cytopathologic grading. RESULTS: The sensitivity for accurate grading was found to be highest for well differentiated (WD) lesions; the specificity was found to be highest for poorly differentiated (PD) HCC for both cytopathologists. Interobserver agreement was highest for WD HCC. WD HCC displayed cohesive fragments, often associated with characteristic vascular/endothelial patterns. In addition, moderately differentiated (MD) HCC demonstrated numerous single cells and atypical naked nuclei, usually with prominent nucleoli. PD HCC displayed loose nests and three-dimensional fragments (often gland-like), pleomorphism, macronucleoli, and focal necrosis. CONCLUSIONS: In the authors' experience, the three-tier cytologic grading of HCC was found to be only moderately accurate. The accuracy of cytologic grading was reported to be high for WD/PD HCC and low for MD HCC. The architectural criteria appear to be more useful for WD HCC, whereas marked cellular pleomorphism is specific for PD HCC. The authors propose that a two-tier grading system may be more useful, given the recent studies of HCC recurrence.

Biopsy, Fine-Needle↗
PubMed2004

Molecular diagnosis of metastasizing oligodendroglioma: a case report.

We report the case of a suspicious parotid mass in which molecular determination of loss of heterozygosity (LOH) of chromosome arms 1p and 19q in combination with cytologic and immunohistochemical analysis defined the tumor to be metastatic oligodendroglioma. The patient was a 41-year-old woman who developed a World Health Organization grade II oligodendroglioma in her right frontal lobe at age 32, for which no adjuvant chemo- or radiotherapy was administered. Five years following this diagnosis, radiological assessment revealed a 10-centimeter mass in the tumor bed, suspicious for a recurrence. Resection of this lesion revealed an anaplastic oligodendroglioma (grade III) and adjuvant radiotherapy was given. Eleven months after this surgery the patient presented with a 5.5-cm subcutaneous, non-mobile, non-tender mass in the region of the right parotid gland. Fine needle aspiration (FNA) yielded highly cellular material, morphologically and immunohistochemically suspicious for oligodendroglioma. Molecular analysis of microsatellite loci residing on chromosome arms 1p and 19q was performed using DNA extracted from the patient's recurrent brain oligodendroglioma and the FNA specimen. This analysis revealed evidence of LOH at all eight of the microsatellite loci tested. The combination of cytologic and molecular findings defined the extracranial tumor to be metastatic oligodendroglioma.

Adult↗