Predictive value of tumor-infiltrating lymphocytes for pathological response to neoadjuvant chemotherapy in breast cancer patients with axillary lymph node metastasis.

PURPOSE: We investigated the role of tumor-infiltrating lymphocytes (TILs) in pretreatment primary breast cancer to predict pathological response to neoadjuvant chemotherapy (NAC) in patients with clinical node-positive disease (cN +). METHODS: The subjects of this study were 60 patients with cN + , who received NAC followed by breast surgery with axillary lymph node dissection (ALND). We conducted a semi-quantitative assessment of TILs in pretreatment primary tumors and their association with clinicopathological factors and axillary lymph node metastasis. RESULTS: We observed a higher number of TILs in tumors with negative hormone receptors, positive human epidermal growth factor receptor 2, or high Ki67. TILs were associated with a favorable response to NAC in primary tumors. The rate of axillary pathologic complete response (Ax-pCR) was significantly higher in patients with a high number of TILs than in patients with a low number of TILs (72.0% versus 17.1%, p < 0.001). In multivariable analysis, a high number of TILs was a significant predictor of Ax-pCR as well as of pCR of the primary tumor after NAC. Importantly, all patients with HER2-positive tumors in the high TILs group showed Ax-pCR on ALND. CONCLUSION: TILs in pretreatment primary breast cancer had the potential to predict therapeutic efficacy of NAC in patients with clinical node-positive disease.

Loss of heterozygosity of chromosome 3p21 is associated with mutant TP53 and better patient survival in non-small-cell lung cancer.

Allelic loss of chromosome region 3p21.3 occurs early and frequently in non-small-cell lung cancer, and numerous tumor suppressor genes at this locus may be targets of inactivation. Using an incident case series study of non-small-cell lung cancer, we sought to determine the prevalence of loss of heterozygosity (LOH) in the 3p21.3 region and to examine the associations between this alteration and patient outcome, exposure to tobacco smoke, occupational asbestos exposure, and additional molecular alterations in these tumors. We examined LOH at 7 microsatellite markers in the chromosome 3p21.3 region, and LOH was present in at least one of the loci examined in 60% (156 of 258) of the tumors, with the prevalence of LOH at individual loci ranging from 15 to 56%. Occupational asbestos exposure and TP53 mutation were significantly associated with more extensive 3p21 LOH. In squamous cell carcinomas, measures of cumulative smoking dose were significantly lower in patients with LOH at 3p21, particularly in TP53 mutant tumors. Examining patient outcome, we found that in squamous cell carcinomas, having any LOH in this region was associated with a better overall survival (log-rank test, P < 0.04). Together, these results indicate that allelic loss at 3p21 can affect patient outcome, and that this loss may initially be related to carcinogen exposure, but that extension of this loss is related to TP53 mutation status and occupational asbestos exposure.

Microsatellite instability at tetranucleotide repeats in skin and bladder cancer.

Recently, a novel form of MSI has been described that occurs only at tetranucleotide repeat markers. This has been termed elevated microsatellite instability at selected tetranucleotide repeats (EMAST). EMAST has been related to alterations of the p53 gene, and to the nature of the repeat sequence. We initially tested whether loss of heterozygosity (LOH) at the p53 and the patched (ptch) genes was related to EMAST in a series of 61 non-melanoma skin cancer (NMSC) tumors. We then analysed a series of 57 primary bladder cancers for the presence of EMAST, testing whether this was related to mutation or expression of the p53 gene. In both NMSC and bladder tumors we found a high prevalence of EMAST (75.4 and 43.9%). In NMSC the prevalence of EMAST was higher in tumors that had either p53 or ptch LOH, although the difference was not statistically significant. There was a significant association of extensive EMAST (three or more loci) with mutations in p53 among the bladder cancer tumors, but no indication of elevated EMAST in tumors with abnormal p53 staining without mutation. The association of EMAST with p53 mutation was confined to non-invasive disease. Hence, EMAST likely reflects a particular pattern of somatic events that are interactive with p53 mutation, particularly common in skin cancer and limited to non-invasive disease in bladder cancer.

Amplification/overexpression of Aurora-A in human gastric carcinoma: potential role in differentiated type gastric carcinogenesis.

Aurora-A encodes a cell cycle regulated serine/threonine kinase that has essential functions for centrosome maturation and chromosome segregation. Aurora-A is amplified and overexpressed in various human carcinomas and is suggested to be a potential oncogene. To clarify the potential role of Aurora-A in human gastric carcinoma, we examined the amplification and expression in both tumor cell lines and primary carcinoma. We examined the amplification and overexpression of Aurora-A in 9 gastric carcinoma cell lines and 88 primary gastric carcinomas using Southern and Northern blot analysis, and confirmed a protein expression by immunohistochemical staining. We also investigated the relationship between Aurora-A overexpression and clinicopathological features of the tumors. Aurora-A amplification and overexpression was observed in 29% and 44.4% of cell lines and 12.5% and 41% of primary carcinomas, respectively. There was discordance between gene amplification and transcript expression, since in a previous study DNA amplification was the main mechanism for Aurora-A activation. Aurora-A overexpression exhibited significant association with increasing age and differentiated type gastric carcinoma. It was also detected in early stage gastric cancer as well as in gastric intestinal metaplasia, which is considered as a common precursor lesion for the differentiated type gastric carcinoma, and severe dysplastic cells showed stronger protein expression. We concluded that Aurora-A overexpression may well be involved in differentiated type gastric carcinogenesis. Further evaluation of the possible roles of Aurora-A and the regulation of Aurora-A expression in malignant cells will be critically important for the development of new strategies aimed at controlling the growth of malignant cells.

Nemo-like kinase suppresses Notch signalling by interfering with formation of the Notch active transcriptional complex.

The Notch signalling pathway has a crucial function in determining cell fates in multiple tissues within metazoan organisms. On binding to ligands, the Notch receptor is cleaved proteolytically and releases its intracellular domain (NotchICD). The NotchICD enters the nucleus and acts cooperatively with other factors to stimulate the transcription of target genes. High levels of Notch-mediated transcriptional activation require the formation of a ternary complex consisting of NotchICD, CSL (CBF-1, suppressor of hairless, LAG-1) and a Mastermind family member. However, it is still not clear how the formation of the ternary complex is regulated. Here we show that Nemo-like kinase (NLK) negatively regulates Notch-dependent transcriptional activation by decreasing the formation of this ternary complex. Using a biochemical screen, we identified Notch as a new substrate of NLK. NLK-phosphorylated Notch1ICD is impaired in its ability to form a transcriptionally active ternary complex. Furthermore, knockdown of NLK leads to hyperactivation of Notch signalling and consequently decreases neurogenesis in zebrafish. Our results both define a new function for NLK and reveal a previously unidentified mode of regulation in the Notch signalling pathway.

TP53 alterations and patterns of carcinogen exposure in a U.S. population-based study of bladder cancer.

The molecular pathology of bladder cancer has been the subject of considerable interest, and current efforts are targeted toward elucidating the interrelationships between individual somatic gene loss and both etiologic and prognostic factors. Mutation of the TP53 gene has been associated with more invasive bladder cancer, and evidence suggests that TP53 mutation, independent of stage, may be predictive of outcome in this disease. However, there is no consensus in the literature that bladder carcinogen exposure is associated with inactivation of the TP53 gene. Work to date has been primarily hospital based and, as such, subject to possible bias associated with selection of more advanced cases for study. We examined exposure relationships with both TP53 gene mutation and TP53 protein alterations in a population-based study of 330 bladder cancer cases in New Hampshire. Tobacco smoking was not associated with TP53 alterations. We found a higher prevalence of TP53 inactivation (i.e., mutation and nuclear accumulation) among hair dye users (odd ratio [OR] = 4.1; 95% confidence interval [CI] 1.2-14.7), and the majority of these mutations were transversions. Men who had "at risk" occupations were more likely to have mutated TP53 tumors (OR = 2.9; 95% CI 1.1-7.6). There also was a relative absence of TP53 mutation (OR = 0.4; 95% CI 0.0-2.9) and TP53 protein alterations (OR = 0.6; 95% CI 0.3-1.4) in bladder cancers from individuals with higher arsenic exposure. Our data suggest that there is exposure-specific heterogeneity in inactivation of the TP53 pathway in bladder cancers and that integration of the spectrum of pathway alterations in population-based approaches (capturing the full range of exposures to bladder carcinogens) may provide important insights into bladder tumorigenesis.

Loss of heterozygosity on chromosome 9q and p53 alterations in human bladder cancer.

BACKGROUND: Somatic loss of the 9q allele as well as alteration of the tumor suppressor p53 occurs commonly in bladder cancers. Although alteration of p53 has been strongly associated with invasive stage disease, the prognostic significance of 9q loss of heterozygosity (LOH) and the relations between these alterations are less well defined. METHODS: The 9q LOH was examined at five microsatellites and p53 alterations (mutation and persistent immunohistochemical staining) in a population-based case series of 271 newly diagnosed bladder cancer patients. Loss of heterozygosity was scored quantitatively and p53 mutation completed using single-strand conformation polymorphism screening followed by sequencing. RESULTS: Overall, allelic loss at 9q was detected in 74.5% (202/271) of cases and allele loss was associated with invasive disease (P < 0.05). Although based on small numbers, all nine in situ lesions contained 9q LOH. Age, gender, and smoking were not significantly associated with chromosome 9q allele loss. Both intense persistent p53 staining and LOH at 9q were independently associated with invasive disease (P < 10(-14) and P < 0.05, respectively). CONCLUSIONS: These data, using a population-based sample, suggest a relation between 9q LOH and invasive stage bladder cancer, and thereby suggests that a tumor suppressor gene at this loci, in addition to p53, may be important in the development of this more aggressive form of the disease.

Alterations of the p16(INK4) locus in human malignant mesothelial tumors.

The INK4 locus has two promoters and encodes two unique proteins that share exons in different reading frames, p16(INK4a) and p14(ARF). The p16(INK4a) protein, by inhibiting cyclin-dependent kinase, down regulates Rb-E2F and leads to cell cycle arrest in the G1 phase. The p14(ARF) protein interacts with the MDM2 protein, neutralizing MDM2-mediated degradation of p53. Since p53/Rb genes are not altered in malignant mesothelioma, additional components of these pathways, such as p16(INK4a) and p14(ARF), are candidates for inactivation. In this study, we have examined p16(INK4a) and p14(ARF) alterations (gene deletion, mutation and promoter methylation) in 45 primary malignant mesothelioma specimens. Fourteen patients (31%) had altered p16; four tumors had a methylated promoter region (8.8%), 10 tumors showed p16 to be deleted (22.2%), and one tumor had a point mutation (2%). We did not find any instances of methylation in the p14(ARF) 5'-CpG island. Patients whose tumors had p16 deletion were significantly younger than those with methylation, and, in the patients whose lungs were studied for the prevalence of asbestos fibers, those with any p16 alteration had lower fiber counts than those with no p16 alteration. Hence, p16 gene alteration is relatively common in malignant mesothelioma, while p14(ARF) is rarely, if ever, methylated. Our data suggest that deletion of p16 occurs in a relatively susceptible subset of the population.