Nuclear CK19-immunopositive pseudoinclusions as a new additional objective diagnostic feature of papillary thyroid carcinoma.

One of the key parameters in the diagnosis of papillary thyroid carcinoma (PTC) are true nuclear pseudoinclusions (NPs), which constitute invaginations of the cytoplasm into the nucleus. On the other hand, strong cytoplasmic expression of CK19 is a well-known attribute of PTC tumor cells. We analyzed NPs using CK19 immunohistochemistry in histological sections of 52 PTCs and seven noninvasive follicular thyroid neoplasms with papillary-like nuclear features (NIFTPs). Strong CK19+ NPs were present in 77% of PTCs, whereas NPs in hematoxylin and eosin (HE)-stained slides (HE NPs) were identified in only 48% of PTCs. Detection of CK19+ NPs enabled easier and objective recognition of NPs and better discrimination of NPs from pseudo-pseudoinclusions than detection of HE NPs. In the 15 of the 27 (55.5%) PTCs in which we could not discern HE NPs, strong CK19+ NPs could be identified reliably, quickly and easily. Moreover, all NIFTPs were negative for both CK19+ NPs and HE NPs. Detection of CK19+ NPs may refine the assessment of this important diagnostic feature and, hence, the microscopic diagnostic criteria of PTC. Thus, these findings may have implications for the accurate diagnosis of PTC and NIFTP.

Fatty acids distribution and content in oral squamous cell carcinoma tissue and its adjacent microenvironment.

Squamous cell carcinoma of the oral cavity mucosa grows under conditions of poor oxygenation and nutrient scarcity. Reprogramming of lipid biosynthesis accompanies tumor growth, but the conditions under which it occurs are not fully understood. The fatty acid content of the serum, tumor tissue and adjacent tumor microenvironment was measured by gas chromatography in 30 patients with squamous cell carcinoma grade 1-3. Twenty-five fatty acids were identified; their frequencies and percentages in each of the environments were assessed. Nineteen of the twenty-five fatty acids were found in tumor tissue, tumor adjacent tissue and blood serum. Of them, 8 were found in all thirty patients. Percentages of C16:0 and C18:1n9 were highest in the tumor, C18:1n9 and C16:0 were highest in tumor adjacent tissue, and C16:0 and C18:0 were highest in blood serum. The frequencies and amounts of C22:1n13, C22:4n6, C22:5n3 and C24:1 in tumor adjacent tissues were higher than those in blood serum, independent of the tumor grade. The correlations between the amount of fatty acid and tumor grade were the strongest in tumor adjacent tissues. The correlations between particular fatty acids were most prevalent for grade 1+2 tumors and were strongest for grade 3 tumors. In the adjacent tumor microenvironment, lipogenesis was controlled by C22:6w3. In blood serum, C18:1trans11 limited the synthesis of long-chain fatty acids. Our research reveals intensive lipid changes in oral cavity SCC adjacent to the tumor microenvironment and blood serum of the patients. Increase in percentage of some of the FAs in the path: blood serum-tumor adjacent microenvironment-tumor, and it is dependent on tumor grade. This dependency is the most visible in the tumor adjacent environment.

BRCA1 and PARP1 mRNA expression during progression from normal breast to ductal carcinoma in situ and invasive breast cancer: a laser microdissection study.

The contribution of DNA damage repair mechanisms to the progression of normal breast to ductal carcinoma in situ (DCIS) and invasive ductal carcinoma is largely unknown. The purpose of this report was to assess the mRNA expression levels of two important genes associated with DNA repair, BRCA1 and PARP1, in normal breast tissue, DCIS G1, G2 and G3, and co-existing adjacent invasive ductal carcinoma. BRCA1 and PARP1 mRNA expression was assessed in 32 ductal carcinomas in situ of the breast using a laser microdissection and pressure catapulting system and quantitative real-time PCR. The relative expression of BRCA1 mRNA was significantly increased in DCIS G2 and DCIS G3 relative to normal breast tissue (p = 0.02, p = 0.001, respectively). Significant differences in BRCA1 expression were observed between DCIS G1 and G2 (p = 0.02) and between DCIS G1 and G3 (p = 0.0007). No significant differences in BRCA1 expression were observed between normal breast tissue and DCIS G1 and between DCIS component and adjacent invasive ductal carcinoma. No significant differences in the relative expression of PARP1 mRNA were observed between groups. Increased BRCA1 mRNA expression (but not PARP1 mRNA) occurs early in the development of breast cancer, i.e. at the noninvasive (DCIS) stage, suggesting a demand for increased activity of a DNA double-strand break repair by homologous recombination. DCIS G1 and normal breast tissue share highly similar BRCA1 and PARP1 expression level. This finding supports the idea that DCIS G1 belongs to a separate family of precursor lesions with low malignant potential.

Immunohistochemical analysis of thymidylate synthase expression in gastric carcinoma: correlation with clinicopathological parameters and survival.

The correlation of thymidylate synthase (TS) expression in gastric cancers with tumor histology and prognostic or predictive information remains unclear. Most studies have involved Asian populations, with few conducted in European cohorts. Moreover, all published studies analyze TS expression using semi-quantitative methods. This retrospective study evaluated the association of TS expression in tumor cells with gastric carcinoma histological type, with selected clinicopathological parameters, and with the prognosis of patients who underwent surgical treatment. TS expression was detected using immunochemistry and objectively assessed by computerized image analysis of tumor cells in 100 gastric cancers. We found that high TS expression was significantly more common in intestinal than in diffuse type of gastric cancer according to Lauren classification (P=0.0003); in type I carcinomas compared to type IV according to Goseki classification (P=0.002); and in gastric cancers in men than women (P=0.04). Low TS expression was found more often in carcinomas in the middle and lower third of the stomach than in cancers in the upper third of the stomach (P=0.009 and P=0.001, respectively). In the subgroup of 25 patients without lymph node metastases (stage I+II), high TS expression was associated with better DFS (83% for high TS expression versus 38,5% for low TS expression, P=0.03). The results (1) indicate significant correlation between the Lauren and Goseki histopathological classifications of gastric cancer and TS expression in tumor cells, (2) suggest that high TS expression may be a positive prognostic marker with regard to DFS in patients with gastric cancer without involvement of regional lymph nodes who underwent radical surgical treatment and were not treated with preoperative chemotherapy. Prognostic results need confirmation in larger cohorts.

E2F1/TS Immunophenotype and Survival of Patients with Colorectal Cancer Treated with 5FU-Based Adjuvant Therapy.

The predictive value of thymidylate synthase (TS) expression alone for 5FU-based treatment of colorectal cancer (CRC) has not been clinically confirmed. Little is known on the association of expression of E2F1, which controls the transcription of genes encoding proteins engaged in DNA synthesis including TS, and survival of patients with CRC. The purpose of this study is to assess the correlation between expression of both E2F1 and TS in CRCs and survival of patients administered adjuvant 5FU-based chemotherapy, in order to find a better predictor of treatment outcome than expression of TS or E2F1 alone. Nuclear TS and E2F1 were detected by immunohistochemistry in tissue microarrays from 190 CRCs (Astler-Coller stage B2 or C). Multivariate analysis identified significant association of the combined E2F1+TS+ immunophenotype with worse OS (HR = 3,78, P = 0,009) and DFS (HR = 2,30, P = 0,03) of patients with colon cancer. There were significant differences between E2F1+TS+ and E2F1-TS- Kaplan-Meier survival curves in relation to DFS (P = 0.008) and OS (P = 0.01). About 37 and 31 % difference in 3-year DFS and OS respectively were seen between patients with E2F1+TS+ vs. E2F1-TS- colon cancer immunophenotype. The E2F1+TS+ immunophenotype may be a marker of poor prognosis (the worst DFS and OS) of patients with colon cancer treated with 5FU-based adjuvant therapy. A subgroup of patients with this immunophenotype may require different and perhaps more aggressive treatment than 5FU-based chemotherapy. Thus, the combined E2F1/TS immunophenotype could be a potential indicator of colon cancer sensitivity to 5FU.

Thymidylate synthase expression and p21(WAF1)/p53 phenotype of colon cancers identify patients who may benefit from 5-fluorouracil based therapy.

BACKGROUND: Studies on the expression of thymidylate synthase (TS) in colorectal cancers (CRCs) have failed to provide unequivocal prognostic or predictive information. Here, we assessed the prognostic significance of TS expression in Astler-Coller stage B2 and C CRCs defined by a p21(WAF1)/p53 immunophenotype in patients subjected to 5-fluorouracil (5FU)-based adjuvant therapy. METHODS: A cohort of 189 CRCs was asssessed for TS, p21(WAF1) and p53 expression on tissue microarrays using immunohistochemistry, and associations with disease-free survival (DFS) and overall survival (OS) of the patients were assessed using univariate and multivariate analyses. RESULTS: TS expression led to the stratification of patients with colon cancer, but not rectal cancer, with immunophenotypes other than p21(WAF1)+/p53- (referred to as P&P) into subgroups characterized by a worse (P&P TS+) and a better (P&P TS-) DFS and OS, in univariate (P = 0.006 and P = 0.005, respectively) and multivariate (P = 0.0004 and P = 0.002, respectively) analyses. The p21(WAF1)+/p53- immunophenotype was associated with a favorable prognosis, irrespective of TS expression. CONCLUSIONS: The strong association observed between the P&P TS+ immunophenotype and a worse DFS and OS suggests a predictive significance of TS expression for 5FU-based adjuvant therapy in patients with colon cancers exhibiting the P&P immunophenotype. In addition, our findings suggest that the appropriate target for assessment of TS expression as a prognostic/predictive marker is a subgroup of colon cancers with an immunophenotype other than p21(WAF1)+/p53-, and that only in this subgroup high TS expression is associated with an unfavorable DFS and OS. Therefore, we suggest that assessing TS expression in conjunction with p21(WAF1)/p53 immunophenotyping of colon cancers may improve the selection of patients suitable for 5FU-based adjuvant chemotherapy.

A common nonsense mutation of the BLM gene and prostate cancer risk and survival.

BACKGROUND: Germline mutations of BRCA2 and NBS1 genes cause inherited recessive chromosomal instability syndromes and predispose to prostate cancer of poor prognosis. Mutations of the BLM gene cause another chromosomal instability clinical syndrome, called Bloom syndrome. Recently, a recurrent truncating mutation of BLM (Q548X) has been associated with a 6-fold increased risk of breast cancer in Russia, Belarus and Ukraine, but its role in prostate cancer etiology and survival has not been investigated yet. METHODS: To establish whether the Q548X allele of the BLM gene is present in Poland, and whether this allele predisposes to poor prognosis prostate cancer, we genotyped 3337 men with prostate cancer and 2604 controls. RESULTS: Q548X was detected in 13 of 3337 (0.4%) men with prostate cancer compared to 15 of 2604 (0.6%) controls (OR=0.7; 95% CI 0.3-1.4). A positive family history of any cancer in a first- or second-degree relative was seen only in 4 of the 13 (30%) mutation positive families, compared to 49% (1485/3001) of the non-carrier families (p=0.3). The mean follow-up was 49months. Survival was similar among carriers of Q548X and non-carriers (HR=1.1; p=0.9). The 5-year survival for men with a BLM mutation was 83%, compared to 72% for mutation-negative cases. CONCLUSIONS: BLM Q548X is a common founder mutation in Poland. We found no evidence that this mutation predisposes one to prostate cancer or affect prostate cancer survival. However, based on the observed 0.6% population frequency of the Q548X allele, we estimate that one in 100,000 children should be affected by Bloom syndrome in Poland.

KRAS mutation testing in colorectal cancer as an example of the pathologist's role in personalized targeted therapy: a practical approach.

Identifying targets for personalized targeted therapy is the pathologist's domain and a treasure. For decades, pathologists have had to learn, understand, adopt and implement many new laboratory techniques as they arrived on the scene. Pathologists successfully integrate the results of those tests into final pathology reports that were, and still are, the basis of clinical therapeutic decisions. The molecular methods are different but no more difficult to comprehend in the era of "kit procedures". In recent years, the development of targeted therapies has influenced routine practices in pathology laboratories because the use of molecular techniques is required to include clinically useful predictive information in the pathology report. Pathologists have the knowledge and expertise to identify particular gene mutations using the appropriate molecular tests currently available. This review focuses on the most important recent developments in KRAS mutation testing in metastatic colorectal cancer (CRC), and shows that a pathologist is involved in 10 stages of this procedure. Recent studies have shown that highly sensitive, simple, reliable and rapid assays may significantly improve the identification of CRC patients resistant to anti-EGFR therapy. Thus, direct sequencing does not seem to be an optimal procedure of KRAS testing for clinical purposes. Twelve currently available high-sensitivity diagnostic assays (with the CE-IVD mark) for KRAS mutation testing are briefly described and compared. The suggested pathology report content for somatic mutation tests is described. In conclusion, evidence is presented that sending away paraffin blocks with tumor tissue for KRAS mutation testing may not be in the best interest of patients. Instead, an evidence-based approach indicates that KRAS mutation testing should be performed in pathology departments, only with the use of CE-IVD/FDA-approved KRAS tests, and with the obligatory, periodic participation in the KRAS EQA scheme organized by the European Society of Pathology as an independent international body.

Different CHEK2 germline mutations are associated with distinct immunophenotypic molecular subtypes of breast cancer.

Germline mutations in BRCA1 were already linked to basal-like subtype of immunophenotypic molecular classification of breast cancer (BC). However, it is not known whether mutations in other BC susceptibility genes are associated with molecular subtypes of this cancer. We tested the hypothesis that distinct mutations in another BC susceptibility gene involved in DNA repair, i.e., CHEK2 may be associated with particular immunophenotypic molecular subtypes of this cancer. Two groups of patients: 1255 with BCs and 5496 healthy controls were genotyped for four CHEK2 mutations (I157T and three truncating mutations: 1100delC, IVS2 + 1G > A, del5395). BCs were tested by immunohistochemistry on tissue microarrays for ER, PR, HER-2, EGFR, and CK5/6 and were assigned to appropriate subtypes of immunophenotypic molecular classification. There was a significant association between CHEK2 mutations and the immunophenotypic molecular classification (P = 0.004). CHEK2-associated cancers were predominantly luminal (108/117 = 92.3%). CHEK2-I157T variant was associated with the luminal A subtype (P = 0.01), whereas CHEK2-truncating mutations were associated with the luminal B subtype (P = 0.005). Comparing the prevalence of CHEK2 mutations in BC with controls revealed that carriers of an I157T variant had OR of 1.80 for luminal A subtype and carriers of truncating mutations had OR of 6.26 for luminal B subtype of BC. To our knowledge, this is the first study showing that specific mutations in the same susceptibility gene are associated with different immunophenotypic molecular subtypes of BC. This association represents independent evidence supporting the biological significance of immunophenotypic molecular classification of BC.

Morphometric distinction of signet-ring cell adenocarcinoma cells from foamy macrophages in gastric endoscopic biopsies.

AIMS: To distinguish signet-ring cancer cells from foamy macrophages in the small gastric endoscopic biopsies using objective morphometric measurements of nuclei. MATERIAL AND METHODS: Using computerized image analysis, the mean nuclear area, length, breadth, perimeter and roundness were analyzed in histological sections of ten gastric endoscopic biopsies with signet-ring cell adenocarcinoma and four benign lesions with numerous foamy macrophages. RESULTS: Nuclei of signet-ring cell adenocarcinoma were significantly bigger than nuclei of foamy macrophages. Mean nuclear area (34.25 µm2 for carcinoma cells vs. 25.41 µm2 for macrophages) and mean nuclear breadth (5.82 µm vs. 4.99 µm, respectively) differed significantly (P < 0.05), whereas the remaining parameters did not. CONCLUSION: Nuclear morphometry can distinguish foamy macrophages from signet-ring cell adenocarcinoma cells in endoscopic gastric biopsies.

Reed-Sternberg cells in classical Hodgkin lymphoma in children seem to be predominantly oestrogen receptor α negative and oestrogen receptor ß positive.

Oestrogen receptor α (ERα) is responsible for activation of gene transcription, while oestrogen receptor ß (ERß) serves as a negative regulator of ERα function. Since ER status is a prognostic and predictive factor in some cancers, we analysed the immunohistochemical expression of ERα and ERß in Reed-Sternberg (RS) cells in paraffin-embedded lymph node specimens from 27 children with classical Hodgkin lymphoma (HL) in relation to histological type, clinical stage, age, and gender. Percentage of RS cells with positive nuclear reaction for the presence of ERα and/or ERß was assessed. ERα positive RS cells were present in 11% (3/27) of lymph nodes (range 1-8%, mean 0.4%) whereas ERß positive RS cells were detected in 96% (26/27) of lymph nodes (range 1-97.5%, mean 61.8%). The highest percentage of ERß positive RS cells was observed in patients with the most advanced (IVB) disease as compared to patients with lower stages (90.3% vs. 56.9% respectively, p = 0.004). To the best of our knowledge this is the first report on the expression of ERß in RS cells in children. We conclude that RS cells in classical HL in children seem to be mainly ERß positive and ERα negative.

Activation of NF-ĸB in leukemic cells in response to initial prednisone therapy in children with acute lymphoblastic leukaemia: relation to other prognostic factors.

Nuclear factor ĸB (NF-ĸB) is a transcription regulator of proliferation and cell death. Increased activation of NF-ĸB may be responsible for treatment failure in children with acute lymphoblastic leukaemia (ALL). This study aimed to assess changes in NF-ĸB activation in peripheral blood mononuclear cells prior to and after 6 and 12 h of prednisone administration in relation to age, initial WBC count at diagnosis and early treatment response in childhood ALL. The study comprised 55 children with de novo ALL. Cells were stained with mouse anti-NF-ĸB (p65) antibody followed by goat anti-mouse antibody conjugated with FITC and measured by laser scanning cytometer. The nuclear/cytoplasmic (N/C) ratio of NF-ĸB reflecting activation of NF-ĸB was decreased 12 h after treatment in the standard risk group patients, whereas it remained statistically unchanged in the non-standard risk group patients. Changes in the N/C ratio of NF-ĸB were not associated with age and early treatment response; however, in children with an initial WBC count higher than 20 000/µl at diagnosis, this ratio was increased after 6 and 12 h from prednisone administration. The association of higher activation of NF-ĸB with an elevated initial WBC count suggests that activation of NF-ĸB may be responsible for treatment failure in children with ALL.

Expression of p21WAF1 in Astler-Coller stage B2 colorectal cancer is associated with survival benefit from 5FU-based adjuvant chemotherapy.

In several, but not all, previous studies, positive p21(WAF1) expression has been suggested as an indicator of a good prognosis in patients with stage III/IV colorectal cancer. However, it is not known whether the same is true for stage B2 patients. The purpose of this study is to assess the influence of p21(WAF1) expression in tumor cells on disease-free survival (DFS) and overall survival (OS) of Astler-Coller stage B2 and C patients with colorectal cancer who underwent 5-fluorouracil-based adjuvant chemotherapy. Nuclear p21(WAF1) was detected by immunohistochemistry in tissue microarrays from 275 colorectal cancers. The expression of p21(WAF1) was associated with DFS (p = 0.025) and OS (p = 0.008) in the subgroup of stage B2 patients that was treated with adjuvant chemotherapy. In multivariate analysis, it remained the only independent prognostic parameter in relation to DFS and OS (p = 0.035 and p = 0.02, respectively). In the subgroup of 72 stage B2 patients with positive p21(WAF1) expression but not in the subgroup of 61 stage B2 patients with negative p21(WAF1) expression, adjuvant chemotherapy was associated with better DFS (85% 5-year survival versus 65% without chemotherapy, p = 0.03) and OS (96% versus 82%, p = 0.014). In the combined stage B2 and C group of patients treated with adjuvant chemotherapy, positive p21(WAF1) expression was also associated with better DFS and OS (p = 0.03, p = 0.002, respectively). Expression of p21(WAF1) in colorectal tumor cells identifies a subgroup of Astler-Coller stage B2 patients who could benefit significantly from 5FU-based chemotherapy and may improve the selection of patients for adjuvant chemotherapy.

PARP-1 expression in breast cancer including BRCA1-associated, triple negative and basal-like tumors: possible implications for PARP-1 inhibitor therapy.

Despite ongoing trials of PARP inhibitors in the treatment of breast cancer (BC), the extent of poly(ADP-ribose)polymerase-1 (PARP-1) protein expression in BCs, which may influence treatment results, is not known. The purpose of this report is to assess expression of PARP-1 in BC including BRCA1-associated, triple negative (TN), and basal-like tumors. Immunohistochemistry with a PARP-1 antibody on tissue microarrays from 130 BRCA1-associated and 594 BRCA1-non-related BCs was used. The vast majority of breast carcinomas expressed high level of nuclear PARP-1 protein and a small percentage of tumors exhibited both nuclear and cytoplasmic PARP-1 expression. There was a significant difference between the mean nuclear PARP-1 quickscore in BRCA1-associated versus BRCA1-non-associated carcinomas in all tumors (P < 0.0001), in the basal-like group (P = 0.0086), TN (P = 0.0015), and non-basal-like groups (P = 0.016) but not in the non-TN group. Among BRCA1-associated BCs, low PARP-1 expression was found in 18.5% of all cases, 18.9% of basal-like and 21% of TN cancers. Among BRCA1-non-related tumors, low PARP-1 expression was found in 8.8% of all cases, 3.1% of basal-like, and 2.7% of TN cancers. PARP-1 expression is significantly associated with BRCA1 status in basal-like and TN BCs. The assessment of PARP-1 expression in tumor samples may improve the selection of BC patients for PARP inhibitor therapy.

Immunophenotypic predictive profiling of BRCA1-associated breast cancer.

The immunophenotypic predictive profile of BRCA1-associated cancers including major predictive markers, i.e., PARP-1, EGFR, c-kit, HER-2, and steroid hormones (ER/PR) that may have therapeutic relevance has not yet been reported in a comprehensive study. Using immunohistochemistry, we examined the expression of these proteins in a large cohort of BRCA1-associated breast cancers. PARP-1 immunoreactivity was found in 81.9%, EGFR in 43.6%, ER/PR in 17.9%, c-kit in 14.7%, and overexpression of HER-2 in 3.6% of cancers. For all markers studied, 8.2% of tumors were negative. Expression of only one predictive marker was found in 29.7% of cancers, and most frequently, it was PARP-1 (20.8%). In 62.1% of tumors, more than one predictive marker was expressed: PARP-1 and EGFR in 30.4%, PARP-1, and hormone receptors in 13.3% and PARP-1 with c-kit in 7.5% of all tumors. Coexpression of two or more other predictive markers was rare. There were significant differences in the median age at diagnosis of BRCA1-associated cancer between patients with ER+ vs. ER- and grades 1-2 vs. grade 3 tumors. These results demonstrate that BRCA1-associated cancers differ with respect to expression of proteins that are regarded as targets for specific therapies and that 92% of patients with BRCA1-associated cancers may benefit from one or several options for specific therapy (in addition to DNA damaging agents, e.g., cisplatin). About 8% of cancers which do not express therapeutic target proteins may not respond to such therapies. Knowledge of the immunophenotypic predictive profile may help with the recruitment of patients for trials of targeted therapies.

Mutational analysis of CDKN2A gene in a group of 390 larynx cancer patients.

CDKN2A gene belongs to the genes involved in cell cycle regulation. When is absent or inactivated by mutation or promoter hypermethylation a cell may undertake an uncontrolled proliferation. Inactivation of CDKN2A gene is observed in many human malignancies, including larynx cancer. In this study we investigated mutations in exon 1 and exon 2 of CDKN2A gene in a large group of 390 laryngeal cancers. We found 40 different alterations (17%) and nearly half of them was not described previously. Out of these alterations two transversions in codon 108: c.322G>C (Asp108His) and c.322G>T (Asp108Tyr) as well as a G>A transition in codon 110 (Trp110X) were found more frequently (altogether: 7 cases in codon 108 and 10 cases in codon 110). This result, concerning the location of these codons in the ankyrin repeat structures, may suggest that these two codons may be critical hot-spots in larynx carcinogenesis.

Simultaneous assessment of p53 and MDM2 expression in leukemic cells in response to initial prednisone therapy in children with acute lymphoblastic leukemia.

Ineffective apoptosis is one of main causes of a treatment failure in childhood acute lymphoblastic leukemia (ALL). p53 plays a crucial role in triggering apoptosis of ALL in response to prednisone treatment. MDM2 is the endogenous inhibitor of apoptosis that downregulates the functional activity of p53 protein. This study is aimed to evaluate changes in MDM2 and p53 expression in peripheral blood mononuclear cells collected from children with ALL prior to and after 6 and 12 h of prednisone administration in relation to early treatment response. The study comprised 35 children with newly diagnosed ALL, subdivided into good (n = 24) and poor (n = 11) early treatment responders. MDM2 - associated APC fluorescence and p53 - associated FITC fluorescence were measured by the laser scanning cytometer. In the group of poor responders, p53 and MDM2 fluorescence were significantly higher than in the group of good responders. In the group of good early treatment responders, a statistically significant rise of p53 fluorescence measured in the nucleus and in the cytoplasm 12 h after prednisone administration as well as increase in MDM2 fluorescence measured in the cytoplasm 6 and 12 h after prednisone administration were seen. These data suggest that pretreatment overexpression of MDM2 protein may contribute to poor early treatment response.

Good early treatment response in childhood acute lymphoblastic leukemia is associated with Bax nuclear accumulation and PARP cleavage.

BACKGROUND: Bax activation and intracellular redistribution as well as its prognostic significance during steroid-induced apoptosis of leukemic cells in childhood acute lymphoblastic leukemia (ALL) remain a matter of controversy. The purpose of this study was to assess time-resolved changes in Bax activation and its intracellular distribution as well as the percentage of apoptotic cells evaluated by PARP cleavage in response to prednisone treatment in childhood ALL. MATERIAL/METHODS: The study comprised 43 children with de novo ALL. Bax activation and PARP cleavage were measured by laser scanning cytometry in peripheral blood mononuclear cells collected prior to and 6 and 12 hours after prednisone administration. RESULTS: The mean pretreatment proportion of p89 PARP-positive cells was 3.5%. Six and twelf hours after prednisone administration it increased significantly (p<0.01) only in the group of good treatment responders. A significant rise (p<0.05) in cytoplasmic Bax expression was seen in the good responders as early as 6 hours after prednisone administration followed by a significant rise in Bax nuclear expression after 12 hours. At the same time points the mean percentage of apoptotic cells as well as Bax expression in the cytoplasm and nucleus remained unchanged in the group of poor responders. CONCLUSIONS: Increased Bax nuclear accumulation (and possibly also aggregation) together with increased PARP cleavage observed within 12 hours after prednisone oral administration were associated with and may predict good outcome in children with newly diagnosed ALL.

Nuclear thymidylate synthase expression in sporadic colorectal cancer depends on the site of the tumor.

Colorectal carcinoma (CRC) is a heterogeneous disease with specific epidemiological, pathological, molecular, and clinical characteristics that depend on the location of the tumor relative to the splenic flexure. Thymidylate synthase (TS) is a major target of 5-fluorouracil-based chemotherapy for CRC and high expression of this enzyme in tumor cells can influence the effect of therapy. We examined differences in TS protein expression in nuclei of tumor cells between CRCs located proximal and distal to the splenic flexure. Nuclear TS was detected by immunohistochemistry with a TS 106 monoclonal antibody on tissue microarrays constructed from 269 CRCs. The median histological score of nuclear TS expression of all proximal tumors was two times higher (p = 0.0003) and in men three times higher (p = 0.00023) than that found in distal tumors. In multivariate analysis which included age, sex, Astler-Coller stage, histological grade, and site, only proximal location of the tumor was identified as an independent factor associated with higher TS expression (odds ratio 2.46, 95% confidence interval = 1.29-4.70, p = 0.0062). These results demonstrate significant differences in nuclear TS expression between proximal and distal cancers and suggest the potential importance of the site of the tumor for proper stratification of patients for chemotherapy.