Pancreatic adenocarcinomas with DNA replication errors (RER+) are associated with wild-type K-ras and characteristic histopathology. Poor differentiation, a syncytial growth pattern, and pushing borders suggest RER+

The clinical and pathological features of carcinomas of the pancreas with DNA replication errors (RER+) have not been characterized. Eighty-two xenografted carcinomas of the pancreas were screened for DNA replication errors using polymerase chain reaction amplification of microsatellite markers. Cases with microsatellite instability in at least two markers of a minimum of five tested were considered RER+. RER status was correlated with histological appearance, karyotype of the carcinomas when available, K-ras mutational status, and patient outcome. Three (3.7%) of the eighty-two carcinomas were RER+. In contrast to typical gland-forming adenocarcinomas of the pancreas, all three RER+ carcinomas were poorly differentiated and had expanding borders and a prominent syncytial growth pattern. Neither a Crohn's-like lymphoid infiltrate nor extracellular mucin production were prominent. Ductal adenocarcinomas of the pancreas typically contain a mutant K-ras gene, yet all three RER+ carcinomas had wild-type K-ras. One of the three RER+ carcinomas was karyotyped and showed a near diploid pattern. All three of the RER+ tumors were removed via Whipple resection. One of the three patients is free of disease 16 months after pancreaticoduodenectomy, one is alive and free of tumor at 52 months but developed two colon carcinomas during this period, and the third died of pancreatic cancer at 4 months. None of the three patients had a family history of colorectal carcinoma. A review of the K-ras wild-type carcinomas in a previously characterized series of pancreatic carcinomas with known K-ras mutational status identified two additional cancers with poor differentiation, a syncytial growth pattern, and pushing borders. Both of the cancers were diploid and both patients were longterm survivors (over 5 years). The inclusion of such patients in previous prognostic studies of pancreas cancer may explain the failure of histological grade to be a predictor of prognosis. These data suggest that DNA replication errors occur in a small percentage of resected carcinomas of the pancreas and that wild-type K-ras gene status and a medullary phenotype characterized by poor differentiation, and expanding pattern of invasion, and syncytial growth should suggest the possibility of DNA replication errors in carcinomas of the pancreas.     

Frequency of replication errors in colorectal cancer and their association with family history

In the Czech Republic, the incidence of Lyme borreliosis (LB) has shown a rising trend since 1988. The goal of this study has been to find out to what extent a selected part of population is aware of ticks and of the relationship between ticks and LB. The study was based on a questionnaire survey. A total of 110 respondents were selected, including 19 secondary school students, 32 blood donors, 44 park-goers, 15 countryside people. As many as 99% of the respondents were aware of the presence of ticks, 91% knew that ticks are sucking blood of humans and animals, 1.8% thought they eat leaves. 74.5% of the respondents expect ticks to reach them from the vegetation while 22% believe that ticks fall from the trees. Furthermore, 87% and 75% of the respondents indicated to have had ticks attached to the skin or to have removed a tick from other persons' skin, respectively. Only 6.7% of them had never come into contact with ticks. 17% of the respondents use disinfectant when removing a tick, while 67% use oil for tick removal. Almost 30% remove ticks with naked hands. Over 14% destroy the ticks by squashing them with naked fingers. Finally, about 11% of the population studied had never heard about LB and 41% were not aware of the risk of tick-borne encephalitis.     

Allelic imbalance study of 16q in human primary breast carcinomas using microsatellite markers

The high incidence of allelic imbalance on the long arm of chromosome 16 in breast cancer suggests its involvement in the development and progression of the tumor. Several loss of heterozygosity (LOH) studies have led to the assignment of commonly deleted regions on 16q where tumor suppressor genes may be located. The most recurrent LOH regions have been 16q22.1 and 16q22.4-qter. The aim of this study was to gain further insight into the occurrence of one or multiple "smallest regions of overlap" on 16q in a new series of breast carcinomas. Hence, a detailed allelic imbalance map was constructed for 46 sporadic breast carcinomas, using 11 polymorphic microsatellite markers located on chromosome 16. Allelic imbalance of one or more markers on 16q was shown by 30 of the 46 tumors (65%). Among these 30 carcinomas, LOH on the long arm of chromosome 16 was detected at all informative loci in 19 (41%); 13 of them showed allelic imbalance on the long but not on the short arm, with the occurrence of variable "breakpoints" in the pericentromeric region. The partial allelic imbalance in 11 tumors involved either the 16q22.1-qter LOH region or interstitial LOH regions. A commonly deleted region was found between D16S421 and D16S289 on 16q22.1 in 29 of the 30 tumors. The present data argue in favor of an important involvement of a tumor suppressor gene mapping to 16q22.1 in the genesis or progression of breast cancer.     

Isolation and characterization of microsatellite markers in the nuclear genome of the brown alga Laminaria digitata (Phaeophyceae)

OBJECTIVE: The authors' goal was to investigate the treatment received by suicide attempters with major depression before and after the index attempt. METHOD: Forty-three patients with current unipolar DSM-III-R major depression were identified in a diagnostic study from a systematic sample of suicide attempters in Helsinki. All were comprehensively interviewed and investigated after the attempt, and their treatment was ascertained from psychiatric and other health care records and follow-up interviews. RESULTS: During the month just before the suicide attempt, seven (16%) of the patients had received antidepressants in adequate doses, seven had received weekly psychotherapy, and none had received ECT. Although almost all of the patients complied with the recommended aftercare following the suicide attempt, after 1 month only seven (17%) were receiving antidepressants in adequate doses, nine (22%) were receiving weekly psychotherapy, and none had been given ECT. CONCLUSIONS: It seems that few suicide attempters with major depression receive adequate treatment for depression before the suicide attempt and that, despite their well-known high risk for suicide, the treatment situation is not necessarily any better after the attempt. These findings suggest that the recognition of depression and the quality of treatment received for major depression among suicide attempters should be investigated and improved to prevent suicide.     

Clinical implications of microsatellite instability in colorectal cancers

BACKGROUND: Microsatellite instability (MI) has been reported in some sporadic colon tumors and in cases of hereditary nonpolyposis colorectal cancer (HNPCC). The criteria for HNPCC have not been fully defined, and clinical criteria are used to identify as many HNPCC patients as possible. To clarify the conformity of these criteria with the identification of eligible HNPCC cases, we analyzed MI in HNPCC patients diagnosed using clinical criteria. METHODS: Genomic DNA was extracted from surgical specimens of 56 colorectal cancers, including 36 from patients diagnosed with HNPCC using the clinical criteria. We analyzed four microsatellite loci using 32P-labeled primers. RESULTS: Among HNPCC patients diagnosed using clinical criteria, patients who were positive for MI accounted for 62% of Group A (a confirmed group) and 35% of Group B (a high risk group); only 5% of randomly selected colorectal cancer patients (Group C), were positive for MI. Furthermore, MI-positive tumors were found in patients who had a tendency for tumors to involve the right side of the colon, an association with cancers in other organs, a lower incidence of p53 protein positivity, and a higher proportion of poorly differentiated cancers. CONCLUSIONS: The presence of MI, in concert with modified clinical criteria, may identify legitimate cases of HNPCC in patients who might otherwise be excluded by the minimum criteria.     

Local genetic structure in red grouse (Lagopus lagopus scoticus): evidence from microsatellite DNA markers

Allelic variation at seven hypervariable tri- and tetranucleotide microsatellite loci was used to determine levels of population differentiation between 14 populations of red grouse (Lagopus lagopus scoticus) in northeast Scotland, UK. Despite the potential for long-distance dispersal in grouse, and a semicontinuous habitat, significant population divergence was observed (mean RST = 0.153; P < 0.01) and an isolation-by-distance effect detected (Mantel test: P < 0.001). Examination of the spatial trend in principal component scores derived from allele frequencies among populations highlighted a barrier to gene flow that was confounding a simple isolation-by-distance effect. This barrier corresponded to an area of unsuitable habitat for grouse associated with a river system that bisected the study area. Mean genetic relatedness was higher for males than for females in all but one of the study populations, suggesting that the territorial behaviour and natal philopatry displayed by cocks have a manifold effect in generating the observed spatial genetic structure. Lower female relatedness values suggest a higher level of female-mediated gene flow, which is sufficient to prevent the loss of genetic variation from within populations and the onset of inbreeding effects. The potential consequences of local subdivision for red grouse populations are discussed.     

Continuing trends in the prevalence of right-sided lesions among colorectal carcinomas

The shift of colorectal carcinoma location toward the proximal colon has been reported. This study documents that this statistically significant trend has continued through 1992. An increase in transverse and descending colon cancers is now apparent also. Only 59% of all large-bowel cancers occurred distal to the descending colon between 1978 and 1992. Both right-sided and distal large-bowel cancers have significantly decreased in size, yet the incidence and frequency of lymph node metastases have not changed over a 65-year interval (from 1928 to 1992). This constant proportion of lymph node metastases may suggest distinct biological subsets of cancers (lymph node avid vs lymph node avoidance). The progression from small size with fewer metastases to large size with more lymph node metastases occurs only in some of the smallest distal colorectal cancers.     

Loss of heterozygosity and microsatellite instability in de novo versus ex-adenoma carcinomas of the colorectum

Small adenocarcinomas of the colorectum showing no evidence of origin from an adenoma have been called de novo carcinomas, a name that implies an origin via a different molecular genetic mechanism than the usual colorectal carcinoma which develops from an adenoma. Using microsatellite analysis, 35 early (pT1) de novo and 36 pT1 ex-adenoma carcinomas were compared using 8 microsatellite loci at 6 different chromosomal loci (1p, 2p, 8p, 5q, 17p, and 18q) known or hypothesized to be important for colorectal carcinogenesis. The rate of loss of heterozygosity (LOH) at the 17p locus (near the p53 gene) was significantly higher in the de novo than in the ex-adenoma group (73 vs. 37%, P = 0.004). The rates of LOH at the other loci (including the APC and DCC genes) and the rate of MSI were not significantly different in the two groups. These results indicate that de novo carcinomas of the colorectum develop via a similar carcinogenetic pathway as conventional ex-adenoma carcinomas; however, their higher rate of LOH at 17p is evidence for a biologically more advanced lesion with more frequent p53 mutations, consistent with clinicopathological data indicating that de novo carcinomas are more aggressive than ex-adenoma carcinomas.     

Analysis of signaling protein kinases in human colon or colorectal carcinomas

Extracellular signal-related kinase (ERK) and c-Jun N-terminal kinase (JNK) mitogen-activated protein (MAP) kinases are highly activated in an in vivo rat model of colorectal carcinogenesis. In addition, other protein kinases such as c-Src and c-Yes have been shown to be up-regulated in some human colon cancers. To evaluate the activity of these kinases in human colorectal carcinomas, we examined colon cancers and adjacent normal intestinal mucosa from 11 patients. Moderate increases in ERK and JNK activities, in addition to up-regulation of c-Src, p125FAK, and tyrosine-phosphorylated proteins, were observed in a subset of the colorectal carcinomas. There was a significant correlation found between levels of c-Src, p125FAK, and tyrosine-phosphorylated proteins, as well as between c-Src protein levels and JNK activity. This is the first report that examines several different kinases as markers to characterize colorectal cancers in the same carcinoma sample, allowing the determination of correlations between markers in the same tumors.