Beneficial Effects of the mTOR Inhibitor Everolimus in Patients with Advanced Medullary Thyroid Carcinoma: Subgroup Results of a Phase II Trial

Objective. Until recently, advanced medullary thyroid cancer (MTC) had few treatment options except surgery. The mTOR inhibitor everolimus has shown encouraging results in neuroendocrine tumors. As part of a prospective phase II study, we analyzed the safety and efficacy of everolimus in advanced MTC. Methods. Seven patients with per RECIST 1.1 documented advanced MTC were included and received everolimus 10 mg daily. The primary objective was determining treatment efficacy. Secondary endpoints included progression-free survival (PFS), overall survival (OS), toxicity, and pharmacokinetics (PK). Results. Median follow-up duration was 28 weeks (17-147). Five patients (71%) showed SD, of which 4 (57%) showed SD >24 weeks. Median PFS and OS were 33 (95%CI: 8-56) and 30 (95%CI: 15-45) weeks, respectively. Toxicity was predominantly grade 1/2 and included mucositis (43%), fatigue (43%), and hypertriglyceridemia (43%). Four MTCs harbored the somatic RET mutation c.2753T>C, p.Met918Thr. The best clinical response was seen in a MEN2A patient. PK characteristics were consistent with phase I data. One patient exhibited extensive toxicity accompanying elevated everolimus plasma concentrations. Conclusions. This study suggests that everolimus exerts clinically relevant antitumor activity in patients with advanced MTC. Given the high level of clinical benefit and the relatively low toxicity profile, further investigation of everolimus in these patients is warranted.

Increased frequency of 20q gain and copy-neutral loss of heterozygosity in mismatch repair proficient familial colorectal carcinomas

Many hereditary nonpolyposis colorectal cancers (CRCs) cannot be explained by Lynch syndrome. Other high penetrance genetic risk factors are likely to play a role in these mismatch repair (MMR)-proficient CRC families. Because genomic profiles of CRC tend to vary with CRC susceptibility syndromes, our aim is to analyze the genomic profile of MMR-proficient familial CRC to obtain insight into the biological basis of MMR-proficient familial CRC. We studied 30 MMR-proficient familial colorectal carcinomas, from 15 families, for genomic aberrations, including gains, physical losses, and copy-neutral loss of heterozygosity LOH (cnLOH) using SNP array comparative genomic hybridization. In addition, we performed somatic mutation analysis for KRAS, BRAF, PIK3CA and GNAS. The frequency of 20q gain (77%) is remarkably increased when compared with sporadic CRC, suggesting that 20q gain is involved in tumor progression of familial CRC. There is also a significant increase in the frequency of cnLOH and, as a consequence, a reduced frequency of physical loss compared with sporadic CRC. The most frequent aberrations observed included gains of 7p, 7q, 8q, 13q, 20p and 20q as well as physical losses of 17p, 18p and 18q. Most of these changes are also observed in sporadic CRC. Mutations in KRAS were identified in 37% of the MMR-proficient CRCs, and mutations in BRAF were identified in 16%. No mutations were identified in PIK3CA or chromosome 20 candidate gene GNAS. We show that the patterns of chromosomal instability of MMR-proficient familial CRC are clearly distinct from those from sporadic CRC. Both the increased gain on chromosome 20 and the increased levels of cnLOH suggest the presence of yet undiscovered germline defects that can, in part, underlie the cancer risk in these families.

High frequency of copy-neutral LOH in MUTYH-associated polyposis carcinomas

Genetic instability is known to drive colorectal carcinogenesis. Generally, a distinction is made between two types of genetic instability: chromosomal instability (CIN) and microsatellite instability (MIN or MSI). Most CIN tumours are aneuploid, whereas MSI tumours are considered near-diploid. However, for MUTYH-associated polyposis (MAP) the genetic instability involved in the carcinogenesis remains unclear, as near-diploid adenomas, aneuploid adenomas and near-diploid carcinomas have been reported. Remarkably, our analysis of 26 MAP carcinomas, using SNP arrays and flow sorting, showed that these tumours are often near-diploid (52%) and mainly contain chromosomal regions of copy-neutral loss of heterozygosity (LOH) (71%). This is in contrast to sporadic colon cancer, where physical loss is the main characteristic. The percentage of chromosomal gains (24%) is comparable to sporadic colorectal cancers with CIN. Furthermore, we verified our scoring of copy-neutral LOH versus physical loss in MAP carcinomas by two methods: fluorescence in situ hybridization, and LOH analysis using polymorphic markers on carcinoma fractions purified by flow sorting. The results presented in this study suggest that copy-neutral LOH is an important mechanism in the tumorigenesis of MAP.

Single nucleotide polymorphism array analysis of chromosomal instability patterns discriminates rectal adenomas from carcinomas

Total mesorectal excision (TME) is the standard treatment for rectal cancer, while transanal endoscopic microsurgery (TEM) is a recently introduced surgical approach for the treatment of rectal adenomas. Incorrect preoperative staging before TEM is a problem. To identify genetic changes that might correlate with tumour stage and could lead to optimized treatment selection we performed a genome-wide chromosomal instability search in a homogeneous, clinical cohort of rectal tumours. 78 rectal tumours during different clinical stages were analysed with 10K single nucleotide polymorphism (SNP) arrays. Logistic regression was performed to build a quantitative model of specific chromosomal aberrations. Overall, most cases (95%) had one or more chromosomal aberrations. We observed a clear correlation between the total number of aberrations and the different tumour stages. Specifically, the chromosomal events: gain of 8q22-24, 13q and 20q, and loss of 17p and 18q12-22, were far more abundant in carcinoma than in adenoma. In adenoma fractions from cases with a carcinoma (infiltrating at least in the submucosa), twice the amount of such 'malignant aberrations' was observed, compared to pure adenomas. Furthermore, combined aberrations such as gain of 13q and loss of 18q were only found in adenomatous fractions of carcinomas and not in benign lesions. Based on these five genomic events associated with carcinoma, a clear distinction between adenoma and carcinoma tissue could be made. These data should be validated further in order that they may be used in preoperative staging of rectal tumours.

E-cadherin transcriptional downregulation by promoter methylation but not mutation is related to epithelial-to-mesenchymal transition in breast cancer cell lines

Using genome-wide expression profiling of a panel of 27 human mammary cell lines with different mechanisms of E-cadherin inactivation, we evaluated the relationship between E-cadherin status and gene expression levels. Expression profiles of cell lines with E-cadherin (CDH1) promoter methylation were significantly different from those with CDH1 expression or, surprisingly, those with CDH1 truncating mutations. Furthermore, we found no significant differentially expressed genes between cell lines with wild-type and mutated CDH1. The expression profile complied with the fibroblastic morphology of the cell lines with promoter methylation, suggestive of epithelial–mesenchymal transition (EMT). All other lines, also the cases with CDH1 mutations, had epithelial features. Three non-tumorigenic mammary cell lines derived from normal breast epithelium also showed CDH1 promoter methylation, a fibroblastic phenotype and expression profile. We suggest that CDH1 promoter methylation, but not mutational inactivation, is part of an entire programme, resulting in EMT and increased invasiveness in breast cancer. The molecular events that are part of this programme can be inferred from the differentially expressed genes and include genes from the TGFβ pathway, transcription factors involved in CDH1 regulation (i.e. ZFHX1B, SNAI2, but not SNAI1, TWIST), annexins, AP1/2 transcription factors and members of the actin and intermediate filament cytoskeleton organisation.

A partial BRCA1 sequence homology mapping to 4q28

Using a BRCA1 cDNA probe in Southern analysis, we detected a sequence of 348 bp on 4q28 that is homologous to the 3' end of BRCA1. A 28-kb sequence contig has been assembled spanning the homologous region, which we designated BRCA1-h. An open reading frame was identified encoding a sequence of 82 amino acids; 22 of the last 23 amino acids are identical to the last 23 residues of BRCA1. BLAST-searches, RT-PCR and RACE-experiments have been unable to provide evidence that BRCA1-h is part of an expressed gene.

Involvement of the CACNA1A gene containing region on 19p13 in migraine with and without aura

OBJECTIVE

To assess the involvement of the 19p13 familial hemiplegic migraine (FHM) locus in migraine with and without aura.

BACKGROUND

Migraine with and without aura are likely to be polygenetic multifactorial disorders. FHM is a rare dominantly inherited type of migraine with aura. In about 50% of families, FHM is caused by mutations in the P/Q-type calcium channel alpha(1A)-subunit (CACNA1A) gene on chromosome 19p13. The CACNA1A gene is thus a good candidate gene for "nonhemiplegic" migraine with or without aura.

METHODS

The authors performed an affected sibpair analysis using flanking and CACNA1A intragenic markers. The authors assessed the occurrence of shared parental marker alleles among 189 affected siblings from 36 extended families with typical migraine with or without aura.

RESULTS

Sibling pairs with any form of migraine had inherited the same 19p13 CACNA1A-containing region significantly more frequently than expected by chance (maximum multipoint lod score = 1.22). This result was almost exclusively dependent on the increased sharing found in sibling pairs with migraine with aura (maximum multipoint lod score = 1.41). The locus-specific relative risk for a sibling (lambda(s)) to suffer from migraine with aura, defined as the increase in risk of the trait attributable to the 19p13 locus, was lambda(s) = 1.56. When combining migraine with and without aura, lambda(s) was 1.22.

CONCLUSIONS

The increased allele sharing in the CACNA1A gene region on 19p13 is consistent with an important involvement of this region in migraine, especially migraine with aura.

Genetic analysis of a breast-ovarian cancer family, with 7 cases of colorectal cancer linked to BRCA1, fails to support a role for BRCA1 in colorectal tumorigenesis

Mutations in the BRCA1 gene cause strongly elevated risks of breast and ovarian cancers but may also confer a 3-fold increased risk for colorectal cancer. To address the relationship between BRCA1 carriership and colorectal tumorigenesis, we studied the genetics of a breast-ovarian cancer family with 7 cases of colorectal cancer. A germline 3938insG mutation in BRCA1 was found in 5 breast-cancer patients, 1 with ductal carcinoma in situ, ovarian cancer and an adenoma of the colon, and in 4/5 colorectal-cancer patients investigated. However, the youngest patient, diagnosed at age 23, was a non-carrier. Loss of the wild-type BRCA1 allele was observed in 3/3 breast tissues (2 breast carcinomas and 1 ductal carcinoma in situ) but in 0/6 colorectal tissues (5 carcinomas and 1 adenoma), suggesting that BRCA1 loss is not critical for colorectal tumorigenesis. To examine the possibility that an as yet unknown gene linked to BRCA1 was involved in the colorectal cancers, chromosome 17 segregation was studied with 7 polymorphic markers encompassing a 20 cM region including BRCA1. None of these markers showed complete allele sharing among all 5 colorectal-cancer patients studied. Clinical history, mutation analysis and microsatellite instability analysis excluded a role for any of the known colorectal-cancer susceptibility genes. In 4 other Dutch families carrying the same BRCA1 mutation, only 1 colorectal-cancer case was reported, of which the carrier status is unknown.

Prevalence of BRCA1 in a hospital-based population of Dutch breast cancer patients

The prevalence of disease-related BRCA1 mutations was investigated in 642 Dutch breast cancer patients not selected for family history or age at diagnosis. They were tested for germline mutations in the BRCA1 gene using an assay which detects small deletions and insertions (DSDI), as well as the two major genomic founder deletions present in the Dutch population. Data on family history and bilateral breast cancer were obtained retrospectively. Ten protein truncating mutations were detected and one in-frame deletion with an unknown relation to disease risk. Four patients carried the Dutch founder deletion of exon 22. Based on these results the estimated prevalence of breast cancer in the general population in the Netherlands attributable to BRCA1 mutations is 2.1%. Under 40 years-of-age and under 50 years-of-age this prevalence is 9.5% and 6. 4%, respectively. All mutation carriers were under 50 years-of-age at diagnosis of the first breast cancer, and five did not have any relative with breast cancer. The proportions of bilateral breast cancer in the mutation carriers and non-carriers did not differ from each other. These data indicate that in the general Dutch breast cancer population the great majority of BRCA1 mutations will be found in women diagnosed under 50 years-of-age.

A meta-analysis of indirect memory tests for novel material in organic amnesics

A meta-analysis was conducted on studies of implicit memory for novel and familiar information in organic amnesic patients and healthy controls. Across studies, the amnesics performed equivalently to the controls on indirect memory tests for familiar information. However, the controls performed better than amnesics for indirect memory tests for novel item and novel associative information. This is in accord with memory theories which suggest that medial temporal lobe structures are essential for encoding and storing arbitrary associations between items or events.

A sporadic breast tumor with a somatically acquired complex genomic rearrangement in BRCA1

Germ-line mutations in BRCA1 cause a substantial proportion of inherited breast cancer, and most result in inactivated BRCA1 proteins upon translation. Tumours developing in BRCA1 mutation carriers generally show loss of the wild-type allele. However, acquired inactivating mutations in BRCA1 in non-inherited breast tumours showing loss of heterozygosity at the gene locus have not been detected so far. Here we provide evidence that such mutations can be detected in a small proportion of breast tumours. Prompted by recent reports of Alu-mediated large genomic rearrangements in BRCA1, we have investigated whether such rearrangements might occur in sporadic breast cancer as well and have been missed thus far by traditional PCR-based mutation screening technology. To this end, we performed Southern blot analysis of 81 apparently sporadic breast tumours using probes covering exons 6-24 and 3 restriction enzymes. We identified 1 case with an acquired rearrangement (1.2%), indicating that BRCA1 inactivation through changes in the primary genomic sequence of the gene is uncommon in breast cancer. Genes Chromosomes Cancer 27:295-302, 2000.

Do novel associative word stem completion and cued recall share the same memory retrieval processes?

The aim of this study was to determine whether word stem completion for novel associations between cue and target words was mediated by automatic unconscious memory processes or effortful memory processes under conscious control. This was done by applying full and divided attention conditions at test to stem completion, cued recall, and recognition, and by administering a questionnaire that probed the memory strategies used by subjects during the completion test. Divided attention had no effect on stem completion performance, but did reduce associative cued recall. Recognition performance was weakened overall by divided attention, but the associative effect was similar under both attention conditions. This suggested that novel associative word stem completion was mediated by automatic retrieval processes. However, the results of the questionnaire indicated that only subjects who attempted to remember the words from the study phase during the completion task showed any novel associative effect. It is concluded that novel association word stem completion and cued recall share automatic retrieval processes, which nevertheless give rise to the experience of remembering.

Variable clinical expression of mutations in the P/Q-type calcium channel gene in familial hemiplegic migraine. Dutch Migraine Genetics Research Group

Familial hemiplegic migraine (FHM) is an autosomal dominant subtype of migraine with aura, with half of the families being assigned to chromosome 19p13. We identified missense mutations in a brain-specific calcium channel alpha1A-subunit (CACNA1A) gene on 19p13 segregating with FHM and truncating mutations in families with episodic ataxia type 2 (EA-2). Expansions of an intragenic CAG repeat have been shown in autosomal dominant cerebellar ataxia (SCA6). Hence, FHM, EA-2, and SCA6 are allelic ion channel disorders. We analyzed the phenotype-genotype relation in three unrelated FHM families with the calcium channel alpha1A-subunit gene mutations I1811L (two families) and V714A (one family). We found mutations in all but three patients with FHM (i.e., three phenocopies). In addition, the I1811L mutation occurred in two patients with "nonhemiplegic" migraine and in one subject without migraine. Cerebellar ataxia was found in both families with the I1811L mutation but not in the family with the V714A mutation. We failed to find expansions of the intragenic CAG repeat in FHM patients with cerebellar ataxia. We conclude that the I1811L mutation causes both FHM and cerebellar ataxia independent of the number of CAG repeats. The I1811L mutation may also occur in "normal" migraine patients, supporting the hypothesis that FHM is part of the migraine spectrum.

BRCA1 genomic deletions are major founder mutations in Dutch breast cancer patients

To date, more than 300 distinct small deletions, insertions and point mutations, mostly leading to premature termination of translation, have been reported in the breast/ovarian-cancer susceptibility gene BRCA1. The elevated frequencies of some mutations in certain ethnic subpopulations are caused by founder effects, rather than by mutation hotspots. Here we report that the currently available mutation spectrum of BRCA1 has been biased by PCR-based mutation-screening methods, such as SSCP, the protein truncation test (PTT) and direct sequencing, using genomic DNA as template. Three large genomic deletions that are not detected by these approaches comprise 36% of all BRCA1 mutations found in Dutch breast-cancer families to date. A 510-bp Alu-mediated deletion comprising exon 22 was found in 8 of 170 breast-cancer families recruited for research purposes and in 6 of 49 probands referred to the Amsterdam Family Cancer Clinic for genetic counselling. In addition, a 3,835-bp Alu-mediated deletion encompassing exon 13 was detected in 4 of 170 research families, while an deletion of approximately 14 kb was detected in a single family [corrected]. Haplotype analyses indicated that each recurrent deletion had a single common ancestor.

Familial hemiplegic migraine and episodic ataxia type-2 are caused by mutations in the Ca2+ channel gene CACNL1A4

Genes for familial hemiplegic migraine (FHM) and episodic ataxia type-2 (EA-2) have been mapped to chromosome 19p13. We characterized a brain-specific P/Q-type Ca2+ channel alpha1-subunit gene, CACNL1A4, covering 300 kb with 47 exons. Sequencing of all exons and their surroundings revealed polymorphic variations, including a (CA)n-repeat (D19S1150), a (CAG)n-repeat in the 3'-UTR, and different types of deleterious mutations in FHM and EA-2. In FHM, we found four different missense mutations in conserved functional domains. One mutation has occurred on two different haplotypes in unrelated FHM families. In EA-2, we found two mutations disrupting the reading frame. Thus, FHM and EA-2 can be considered as allelic channelopathies. A similar etiology may be involved in common types of migraine.

A 3-Mb region for the familial hemiplegic migraine locus on 19p13.1-p13.2: exclusion of PRKCSH as a candidate gene. Dutch Migraine Genetic Research Group

Familial hemiplegic migraine (FHM) is an autosomal domianant subtype of migraine with attacks, associated with transient episodes of hemiparesis. One of the genes for FHM has been assigned to chromosome 19p13. Detailed analysis of critical recombinants from two different chromosome 19-linked FHM families, using new markers indicated a 6-cM candidate region on 19p13.1-p13.2 flanked by loci D19S394 and D19S226. Another paroxysmal neurological disorder, episodic ataxia type 2 (EA-2), has also been linked to the same chromosomal region. Most of the interval was completely covered by YAC and cosmid contigs; the physical map yielded approximately 3 Mb encompassing several genes including the protein kinase substrate 80K-H (PRKCSH) gene. Since PRKCSH is involved in neuronal signal transduction, it was considered to be an FHM candidate gene. The genomic structure of this gene was established and mutation analysis for all exon and flanking intron sequences was performed in FHM- and EA-2-affected individuals. Five polymorphisms were identified, including a trinucleotide repeat length variation in the coding sequence. However, no potential disease causing mutation was found and therefore the PRKCSH gene can be excluded for both FHM and EA-2.

Familial hemiplegic migraine locus on 19p13 is involved in the common forms of migraine with and without aura

Migraine is a common neurological disease of two main types: migraine with aura and migraine without aura. Familial clustering suggests that genetic factors are involved in the etiology of migraine. Recently, a gene for familial hemiplegic migraine, a rare autosomal dominant subtype of migraine with aura, was mapped to chromosome 19p13. We tested the involvement of this chromosomal region in 28 unrelated families with the common forms of migraine with and without aura, by following the transmission of the highly informative marker D19S394. Sib-pair analysis showed that affected sibs shared the same marker allele more frequently than expected by chance. Our findings thus also suggest the involvement of a gene on 19p13 in the etiology of the common forms of migraine.

Mutation in DHP receptor alpha 1 subunit (CACLN1A3) gene in a Dutch family with hypokalaemic periodic paralysis

Hypokalaemic periodic paralysis (HypoPP) is characterised by transient attacks of muscle weakness of varying duration and severity accompanied by a drop in serum potassium concentration during the attacks. The largest known HypoPP family is of Dutch origin and consists of 277 members in the last five generations, 55 of whom have HypoPP inherited in an autosomal dominant pattern. Forty-eight persons including 28 patients with a proven diagnosis of HypoPP were used for linkage analysis. Microsatellite markers were used to exclude 45 to 50% of the genome and linkage to chromosome 1q31-32 was found. No recombinants were found between HypoPP and D1S412 and a microsatellite contained within the DHP receptor alpha 1 subunit (CACLN1A3) gene. A previously reported G to A mutation causing an arginine to histidine substitution at residue 528 in the transmembrane segment IIS4 of the CACLN1A3 gene was shown in patients by restriction analysis of genomic PCR products.

Genetic heterogeneity of familial hemiplegic migraine

Familial hemiplegic migraine (FHM) is a distinctive form of migraine with an autosomal dominant mode of inheritance. The migraine-like attacks are associated with transient hemiparesis. A locus for FHM has recently been assigned to chromosome 19 by linkage mapping. In the present study, five unrelated pedigrees with multiple members suffering from hemiplegic migraine were investigated. In two of the pedigrees additional symptoms, cerebellar ataxia and benign neonatal convulsions, respectively, were observed in affected members. Three pedigrees showed linkage to loci D19S391, D19S221, and D19S226 at chromosome 19p13. Haplotyping suggested a location of a FHM gene between D19S391 and D19S221. In the two remaining families, evidence against linkage was found. These results confirm the localization of a gene for familial hemiplegic migraine to the short arm of chromosome 19, but locus heterogeneity not corresponding to the observed clinical heterogeneity is likely to exist.

Chromosome 4 localization of a second gene for autosomal dominant polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) is a genetically heterogeneous disorder. A gene defect located on the short arm of chromosome 16 is responsible for the disease in roughly 86% of affected European families. Using highly polymorphic microsatellite DNA markers, we have assigned a second gene for ADPKD to chromosome 4. In eight families with clear evidence against linkage to chromosome 16 markers, linkage analysis with the markers D4S231 and D4S423, demonstrated a multipoint lod score of 22.42.

Preserved pattern completion priming for novel, abstract geometric shapes in amnesics of several aetiologies

Two experiments were conducted using a paradigm developed by Gabrieli et al., Neuropsychologia 28, 417-427, 1990, which assessed both indirect and direct memory performance in a completion task for novel abstract geometric patterns. The preferred method of scoring was the lines method, based on the number of correct and incorrect lines produced for each item. It was chosen because it is both the simplest and the most informative measure. Two methods of scoring were used in previous work, namely, the strict whole figure method and the lenient whole figure method (Gabrielli et al., 1990; Verfaelie et al., Brain Cognit. 18, 34-45, 1992). Therefore to facilitate comparisons between studies and to determine the characteristics of different scoring methods, results with all three measures were included. In Experiment 1, two different encoding strategies of naming and copying were used in order to explore the relationship between indirect and direct memory performance. Indirect memory performance in the naming condition was at baseline whereas in the copying condition it was significantly above baseline. Cued recall did not differ across encoding conditions but recognition was higher in the naming condition than the copying condition. In Experiment 2, an attempt was made to extend the findings of two studies, one with H.M. (Gabrielli et al., 1990) and one with nine Korsakoffs (Verfaelie et al., 1992), to a larger group of 14 amnesics of several aetiologies. Indirect memory performance was found to be equivalent for the amnesics and their matched controls, only when the lenient and the lines methods of scoring were used. Recognition and cued recall performance was impaired for the amnesics compared to the controls.

Opposite effects of adenosine on two types of cAMP-induced gene expression in Dictyostelium indicate the involvement of at least two different intracellular pathways for the transduction of cAMP signals

Adenosine promotes the cAMP-induced increase of mRNAs, probed with the cDNAs D11 and D14, which are preferentially expressed in prestalk cells, while it inhibits cAMP-induced prespore gene expression. Half-maximal inhibition of prespore gene expression occurs at about 300 muM, while prestalk stimulation by adenosine occurs at about 100-fold lower concentrations and requires the presence of cAMP. These results indicate that adenosine interferes with the transduction to cAMP to gene expression and suggest the involvement of two different adenosine target sites. Our data furthermore indicate that the transduction of extracellular cAMP to prespore gene or prestalk gene expression occurs via divergent pathways.