Prognosis and molecular characteristics of IBD-associated colorectal cancer: Experience from a French tertiary-care center

BACKGROUND

Little is known about the prognosis of colorectal cancer associated with inflammatory bowel disease (CRC-IBD) in a real-world cohort in France.

METHODS

We conducted a retrospective observational study including all patients presenting CRC-IBD in a French tertiary center.

RESULTS

Among 6510 patients, the rate of CRC was 0.8% with a median delay of 19.5 years after IBD diagnosis (median age 46 years, ulcerative colitis 59%, initially localized tumor 69%). There was a previous exposure to immunosuppressants (IS) in 57% and anti-TNF in 29% of the cases. A RAS mutation was observed in only 13% of metastatic patients. OS of the whole cohort was 45 months. OS and PFS of synchronous metastatic patients was 20.4 months and 8.5 months respectively. Among the patients with localized tumor those previously exposed to IS had a better PFS (39 months vs 23 months; p = 0.05) and OS (74 vs 44 months; p = 0.03). The IBD relapse rate was 4%. No unexpected chemotherapy side-effect was observed CONCLUSIONS: OS of CRC-IBD is poor in metastatic patients although IBD is not associated with under-exposure or increased toxicity to chemotherapy. Previous IS exposure may be associated with a better prognosis.

BIRC5 (survivin): a pejorative prognostic marker in stage II/III breast cancer with no response to neoadjuvant chemotherapy

PURPOSE

Neoadjuvant systemic therapy (NAC) is currently used in the treatment of stage II/III breast cancer. Pathological complete response as a surrogate endpoint for clinical outcomes is not completely validated for all subgroups of breast cancers. Therefore, there is a need for reliable predictive tests of the most effective treatment.

METHODS

We used a combination of predictive clinical, pathological, and gene expression-based markers of response to NAC in a prospective phase II multicentre randomized clinical trial in breast cancer patients, with a long follow-up (8 years). This study concerned the subpopulation of 188 patients with similar levels of pathological response rates to sequential epirubicin/cyclophosphamide and docetaxel to determine predictive marker of pCR and DFS. We used a set of 45 genes selected from high throughput analysis and a standardized RT-qPCR. We analyzed the predictive markers of pathological complete response (pCR) and DFS in the overall population and DFS the subpopulation of 159 patients with no pCR.

RESULTS

In the overall population, combining both clinical and genomic variables, large tumor size, low TFF1, and MYBL2 overexpression were significantly associated with pCR. T4 Stage, lymphovascular invasion, negative PR status, histological type, and high values of CCNB1 were associated with DFS. In the no pCR population, only lymphovascular invasion and high values of BIRC5 were associated with DFS.

CONCLUSIONS

We confirm the importance of ER-related and proliferation genes in the prediction of pCR in NAC-treated breast cancer patients. Furthermore, we identified BIRC5 (survivin) as a main pejorative prognostic factor in patients with breast cancers with no pCR. These results also open perspective for predictive markers of new targeted therapies.

Long-term survival of advanced triple-negative breast cancers with a dose-intense cyclophosphamide/anthracycline neoadjuvant regimen

BACKGROUND

Triple-negative (TN) breast cancers exhibit major initial responses to neoadjuvant chemotherapy, but generally have a poor outcome. Because of the lack of validated drug targets, chemotherapy remains an important therapeutic tool in these cancers.

METHODS

We report the survival of two consecutive series of 267 locally advanced breast cancers (LABC) treated with two different neoadjuvant regimens, either a dose-dense and dose-intense cyclophosphamide-anthracycline (AC) association (historically called SIM) or a conventional sequential association of cyclophosphamide and anthracycline, followed by taxanes (EC-T). We compared pathological responses and survival rates of these two groups and studied their association with tumours features.

RESULTS

Although the two regimens showed equivalent pathological complete response (pCR) in the whole population (16 and 12%), the SIM regimen yielded a non-statistically higher pCR rate than EC-T (48% vs 24%, P=0.087) in TN tumours. In the SIM protocol, DFS was statistically higher for TN than for non-TN patients (P=0.019), although we showed that the TN status was associated with an increased initial risk of recurrence in both regimens. This effect gradually decreased and after 2 years, TN was associated with a significantly decreased likelihood of relapse in SIM-treated LABC (hazard ratio (HR)=0.25 (95% CI: 0.07-0.86), P=0.028).

CONCLUSIONS

AC dose intensification treatment is associated with a very favourable long-term survival rate in TN breast cancers. These observations call for a prospective assessment of such dose-intense AC-based regimens in locally advanced TN tumours.

P2-02-09: TP53 Mutation Patterns in Breast Cancer Subgroups

Tumor protein 53 (TP53) is the most commonly altered gene in human cancers. In breast cancers, TP53 is mutated in approximately 30% of all cases, but this frequency fluctuates widely within the different molecular subclasses. Different types of mutations may be observed, such as substitutions (replacement of a nucleotide pair by another one), or complex mutations (deletions or insertions of one or more nucleotides). Mutation types may reflect mechanism of DNA lesion or DNA repair deficiencies. Furthermore, mutations can give rise to different effects such as truncating mutations leading to loss of function, or missense mutations often leading to dominant negative activity. Those mutation effects can be advantageous in tumorigenesis and thus can be subject to selective pressure.

Here we classified 572 breast tumors in three groups, according to microarray data: luminal, basal and molecular apocrine. TP53 status was assessed by a yeast-based functional assay (FASAY) and cDNA sequencing. We then assessed whether any feature of TP53 mutations would be preferentially associated to a specific subtype of breast cancer.

- In term of TP53 mutation frequencies, as expected, lowest frequency was observed in luminal subgroup (26%) and highest in basal (90%) and molecular apocrine (70%). Notably, much higher rate of TP53 mutations occurred in luminal B subgroup (41%) than in luminal A one (17%), suggesting that TP53 may be an important feature in progression from luminal A to B.

- In term of mutations types, luminal tumors showed high frequency of substitutions, while molecular apocrine and basal presented increased rate of deletions and insertions, reflecting probably increased rate of DNA breaks. This suggests that same mutational events may occur in basal and molecular apocrine tumors.

- In term of mutation effects, we found high frequency of missense mutations in luminal tumors (notably AT to GC) and much higher rate of truncating mutations in basal tumors. These observations point to an existence of different selection pressure in each of them, such as a strong pressure for P53 mutations with potential dominant negative inhibition of P73/P63 (recently shown to favor invasion), in luminal tumors. Collectively, these results point not only to different mechanisms of P53 gene inactivation, but also different functional consequences among the different breast cancer subclasses.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-02-09.

P3-05-01: Gene Profiling of Histopathologically Characterized Apocrine Breast Cancers

Background

Breast cancer is currently classified in 3 groups based on estrogen receptor alpha (ER) and human epidermal growth factor receptor 2 (HER2/ERBB2) gene expression: one basal-like (ER-ERBB2-), one HER2−enriched (ERBB2+) and one luminal (ER+). Yet, in transcriptome-based classifications, ER-ERBB2+ group partially overlaps with more recently defined ER-AR+ (androgen receptor positive) group. This type was named molecular apocrine, in reference to the histopathologically characterized apocrine carcinomas (H-Apo), in which a marked activation of AR signaling was demonstrated with a distinct proteomic signature. H-Apo tumors correspond to 1% of invasive breast carcinomas and are clearly morphological distinct from other AR+ tumors. However, no specific H-Apo transcriptome signature has been reported for this sub-group. In an effort to better characterize those tumors, we have performed a meta-analysis of genomic data, focusing on the ER- AR+ breast subset.

Samples and Methods: Chips were from Affymetrix array generations HG-U133. 258 profiles were unpublished and 1145 were from published or in press data. Gene expression was carried out after GC-RMA normalization. Unsupervised hierarchical clustering and other statistical analysis were performed with R software.

Results: 160 of the 1403 investigated tumors were ER-AR+. An unsupervised hierarchical clustering clearly identified a small subgroup of 14 closely tumors expressing high transcripts levels of PIP, HPGD, ACSM1, AR, SDR5A1, HS3DB1. This profile was very similar to the proteomic signature previously described for the H-Apo tumors. In addition, the pathology report, although available only for 4 of those14 tumors, described them as typical apocrine carcinomas. Taken together, these data suggested that this cluster was the H-Apo subgroup. Unexpectedly, when using the transcriptomic PAM50 classification, 13 were classified as Luminal and only 1 as HER2−enriched, although the 14 tumors were all ER-negative. CGH analysis with Agilent 244K chips was carried out with 25 ER- AR+ tumors, of which 5 were H-Apo carcinomas. Importantly, those 5 H-Apo tumors exhibited fewer DNA lesions than the other ER-AR+ apocrine tumors (17% copy number alterations in H-Apo group versus 41%, p=0.02). More CGH data are currently under investigations and will be discussed.

Discussion: The histopathologically characterized apocrine carcinomas (H-Apo) display transcriptomic signs of active androgen metabolism and fewer DNA lesions than others molecular apocrine tumors. This could suggest that molecular apocrine and H-apocrine tumor derive from the same cell of origin, but that only H-Apo retains morphological apocrine features, possibly due to the presence of fewer genetic lesions. In any case, the prominent androgen signaling activation warrants functional assays of anti-androgen in these breast cancer subtypes.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P3-05-01.

A refined molecular taxonomy of breast cancer

The current histoclinical breast cancer classification is simple but imprecise. Several molecular classifications of breast cancers based on expression profiling have been proposed as alternatives. However, their reliability and clinical utility have been repeatedly questioned, notably because most of them were derived from relatively small initial patient populations. We analyzed the transcriptomes of 537 breast tumors using three unsupervised classification methods. A core subset of 355 tumors was assigned to six clusters by all three methods. These six subgroups overlapped with previously defined molecular classes of breast cancer, but also showed important differences, notably the absence of an ERBB2 subgroup and the division of the large luminal ER+ group into four subgroups, two of them being highly proliferative. Of the six subgroups, four were ER+/PR+/AR+, one was ER−/PR−/AR+ and one was triple negative (AR−/ER−/PR−). ERBB2-amplified tumors were split between the ER−/PR−/AR+ subgroup and the highly proliferative ER+ LumC subgroup. Importantly, each of these six molecular subgroups showed specific copy-number alterations. Gene expression changes were correlated to specific signaling pathways. Each of these six subgroups showed very significant differences in tumor grade, metastatic sites, relapse-free survival or response to chemotherapy. All these findings were validated on large external datasets including more than 3000 tumors. Our data thus indicate that these six molecular subgroups represent well-defined clinico-biological entities of breast cancer. Their identification should facilitate the detection of novel prognostic factors or therapeutical targets in breast cancer.

Abstract P1-17-03: Comparison of Long Term Outcome of Locally Advanced and Inflammatory Breast Cancers Treated with Dose Dense Neoadjuvant Chemotherapy

Background: Inflammatory breast cancers (IBC) have a worse prognosis than locally advanced breast cancer (LABC) (KW Hance, JNCI 2005; 97:966-75). We report a series of LABC and IBC treated with dose dense anthracycline and cyclophosphamide and report the correlation between phenotypic features, pathological complete response (pCR) and disease free survival (DFS).

Materials and methods: Between 1990 and 2003, 196 patients (pts) with LABC (105 pts) and IBC (91 pts) treated at St Louis hospital received

6 cycles (c) of dose dense Cyclophophamid (1.2g/m2 d1)-Epirubicin (E) (75mg/m2d1) q2w (SIM regimen). 133 patients had frozen biopsy allowing p53 determination. Surgery was done after chemotherapy. pCR was defined as no residual invasive tumor in breast and lymph nodes.

Results: Median follow-up was 110 months. IBC were more often ER negative than LABC(52 % vs 34%), more often triple negative (33 % vs 22 %) and more often TP53 mutations .(60% vs 39 %).

pCR in breast and lymph nodes was identical in LABC (17 pts,16%) and in IBC (14 pts, 16 %).

Table I Pathological response and factors associated with pCR

Negative ER and presence of TP53 mutations were strong predictive factors of chemotherapy efficacy in LABC and less in IBCS. histologically grade 3 was not predictive in IBC.

Median disease free survival (DFS) was higher in LABC [103 months (m)] than in IBC (54 m), p=.031. Median Overall survival (OS) was not reached in LABC and was of 134 m in IBC (p = .015). A significant effect of ER status on DFS was found in LABC and IBC. When adjusting for ER, IBC still had a significantly shorter DFS (HR 1.64, 95%CI 1.12 to 2.39, P=.011). Similar results were found for OS. For TP 53, a significant interaction was found with LABC/IBC (p=0.017) with a risk for mutated patients in LABC (p=0.004) and a slight and nonsignificant increased risk in IBC patients (p=0.62).

Estimated disease free survival at 15 years

Conclusion: High risk patients treated with dose dense cyclophosphamide and anthracyclin have very long survival rate. Negativity of ER and p53 mutations are strong predictive factors of good outcome in LABC but less in IBC. This approach in ER-LABC should be prospectively studied..

Abstract P6-05-06: Clinical Presentation of Molecular Apocrine Subgroup of Breast Cancer: A Rather Aggressive Group of Tumor

Background: Estrogen receptor negative (ER-) breast cancer represents 30% of breast cancers. This heterogeneous group comprises at least the basal and HER2+ subgroups. Recent data, as well as our own, has observed that the HER2+ subtype is highly heterogeneous. Several teams have identified a new “apocrine” molecular subgroup of cancer, characterized by androgen receptor (AR) expresion in an ER-context. Here, we have retrospectively identified, based on a transcriptionnal signature, these apocrine molecular tumours and described their clinical presentation and evolution.

Material and Methods:

We retrospectively identified 60 patients treated in St Louis Hospital (Paris) from 1995 to 2008 and presenting the signature of the molecular apocrine subgroup (ERA-, AR+, FOXA1+) by Q-RT-PCR.

Results:

Mean age at diagnosis was 53,5 y.o. Tumours size were T2 or more in 78% cases. Histological types were ductal invasive with intraductal component (n=22), histological apocrine (n=3), and paget disease (n=4). Tumor grade was 3 in 68%, and 2 in 21%, with lymphovascular invasion in 37%. Excluding patients receiving neo-adjuvant chemotherapy, lymph node status was negative in 41%, and positive in 52% (1 to 3, 32%, more than 4N+, 20%). By immunohistochemistry 97.4% were PR-and 58.72% overexpressed HER2.

Surgery was conservative in 46%, and 48% patients underwent mastectomy. Sixteen patients received neoadjuvant chemotherapy (27%), 41 received adjuvant chemotherapy (68%), 16 received hormonal therapy (27%), and

16 received trastuzumab (27%). With a median follow up of 60 months, 34 events (local recurrence n=9, contralateral n=3, distant metastasis n=22), and 13 deaths occurred. Median disease free survival was 48 months.

Discussion:

In this cohort of apocrine molecular carcinomas, tumor phenotypes appears to be rather aggressive, with a high proportion of poor prognosis factors (grade SBR3, lymphovascular invasion, node involvement), and are generally well-correlated to a poor clinical outcome in this population that received heterogeneous treatments. Further data are needed to precisely characterise this particular breast cancer subtype, notably patients who are not eligible to Herceptin-based regimen.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P6-05-06.

Correlation between 18F Fluorodeoxyglucose (FDG) Uptake and Tumor Characteristics in Locally Advanced Breast Cancers

Background: This study analysed the correlation between [18F]fluorodeoxyglucose (FDG) uptake, assessed by positron emission tomography (PET), and prognostic factors in locally advanced breast cancersMaterial and Methods: All locally advanced breast cancers seen at Saint Louis hospital and treated with neo-adjuvant chemotherapy (NAC) have a FDG PET after core needle biopsy and before chemotherapy. We correlated the tumor characteristics: T-stage, histological grade, estrogen and progesterone receptors, c-erbB2 over-expression (immuno-histochemistry determination) and P53 (determinate on frozen biopsies by the FASAYmethod) to FDG standardized uptake value (SUV max). The statistics tests used are student test (comparison of 2 means) and kendall correlation.Results: From June 2006 to April 2009, 91 patients with locally advanced breast tumors have both PET scan and frozen tissue before NAC. Median age at diagnosis is 48 (26-81) and 45 % are post menopausal.Conclusion: This study indicates that FDG-PET uptake is correlated with the phenotype of breast tumours. Over-expression of c-erbB2 does not influence FDG uptake. Triple negative tumours and p53 mutated tumors have a high initial SUV which can reflect their aggressiveness and their chemotherapy sensitivity. The knowledge of SUV uptake according to tumor characteristics allows a better understanding of the role of FDG-PET in the prediction of neoadjuvant chemotherapy response.Patients characteristicsPtes characteristicsNumber of patients (%)Tumor size: T2/T3/T438 (41)/32 (35)/21(23)Lymph nodes N0/N1/N232 (35)/46 (50.5)/13 (14 )Invasive ductal carcinoma/invasive lobular carcinoma/miscellaneous82 (90 )/5 (5 )/3 (3)Histological grade/ 1/2/37 (7 )/49 (54)/35 (38)ER + / ER-58 (64 )/33 (36)PR+ /PR-35 (38) /56 (61)C-erbB2 +++15 (16 )Triple negative22 (24 )P53 ( 64 ptes) mutated/wild type32 (50)/32 (50) 

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5010.

Do Transcriptomic Markers Provide Significant and Stable Information in Addition to Standard Markers, for the Prediction of Pathological Complete Response in Breast Cancer?

Background: The aim of this study was to investigate and quantify the contribution of transcriptomic markers, in addition to strong predictors such as oestrogen receptor status, to the prediction of pathological complete response (pCR) in locally advanced breast cancer.Patients: The RNA profiles were analyzed using U133 plus 2.0 Affymetrix. We included 189 patients out of 340 patients entered in a neoadjuvant chemotherapy trial for large operable and locally advanced breast cancer. After four cycles of epirubicin–cyclophosphamide, patients were randomly allocated to four cycles of docetaxel with or without celecoxib for patients with HER2-negative tumors, and docetaxel with or without trastuzumab for patients with HER2-positive tumors, respectively. Proportions of pCR in each group were equal to 0.12, 0.16, 0.15 and 0.24 respectively. Patients who received trastuzumab (N=36) were discard from our example, in order to deal with similar proportions of pCR.Methods: The whole sample was divided into a training set (N=81) and a validation set (N=72). Using the training set, two predictive models were built using multivariate logistic regression models. In the first model (M1), usual clinical and biological significant markers were included. In the second model (M2), in addition to the significant parameters of M1, significant transcriptomic variables were included. Diagnostics of both predictive models were assessed on the validation set through sensitivity and specificity estimates. Simulations were performed to investigate stability of model M2.Results: In M1, oestrogen receptor status and tumor size were found to have a strong predictive role in the prediction of pCR. In addition to these classical markers, genes belonging to biological pathways involved in proliferation and microtubule stabilization appeared to have a strong role in the prediction of pCR (model M2). Validation of M1 on the validation set provided 70% of sensitivity and 86% of specificity. Validation of M2 on the validation set yielded to a better sensitivity of 80% and a specificity of 81%. Using simulations, we showed that several different predictive models M2 yielded to similar performances on the validation set. Conclusion: Our study showed that transcriptomic markers provided significant information in addition to usual biological markers for the prediction of pCR. In addition, predictive model with both usual and transcriptomic markers may lead in an improvement of the classification performances. However, as illustrated by simulations, predictive models with both classical and transcriptomic markers are not exclusive. The contribution of transcriptomic data for the prediction of pCR is straightforward, but finding a stable predictive model remains a great challenge.Supported by PHRC AOM/2OO2/02117, Pfizer inc., Roche, sanofi-aventis.ISRCTN10059974

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2035.

Clinical Subtype-Derived p53 Gene Signature Is Predictive of Prognosis and Response to Chemotherapy in ER-Positive but Not in ER-Negative Breast Cancers

BackgroundBreast cancer is a collection of molecularly distinct neoplastic diseases and therefore, we hypothesized that p53 gene mutations may lead to different transcriptional changes in the different molecular subtypes and these may translate into subtype-dependent prognostic and predictive values.MethodsWe developed gene expression-based predictors of p53 status separately for estrogen receptor-positive (ER+) and -negative (ER-) breast cancers from a publicly available data set with known p53 mutation status (n=251). We validated the two signatures on an independent cohort of cancers (n=103) with known p53 functional status and tested their prognostic and predictive values on two other cohorts of breast cancers that received no systemic adjuvant therapy (n=255; n=198), and on one cohort of ER+ patients treated with adjuvant tamoxifen (n=277). We also examined if the p53 signatures were associated with chemotherapy sensitivity in ER+ and ER- cancers, respectively in two separate neoadjuvant data sets (n=233; n=103).ResultsWe developed a 39-gene p53 signature derived from 213 ER+ and a 30-gene p53 signature derived from 38 ER- breast cancers with no overlapping genes. External validation showed a sensitivity and specificity of 89% and 54%, respectively for the 39-gene signature in ER+ breast cancers; and 82% and 61%, respectively for the 30-gene signature in ER- cancers. The 39-gene signature was predictive of worse distant metastasis free survival (DMFS) in ER+ cancers with p53 dysfunction in both prognostic data sets (Hazard ratio (HR): 2.3 (95% confidence interval (CI):1.25-4.23, p=0.005 and HR:2.17 (95%CI:0.85-5.56, p=0.09). It remained predictive of worse DMFS even after tamoxifen adjuvant therapy (HR=2.43, 95%CI: 1.35-4.38, p<0.0001). In contrast it was associated with higher chemotherapy sensitivity in ER+ cancers. Its predictive accuracy for pathologic complete response was of 68% (95%CI: 64-70%), sensitivity 89% (95%CI: 58-98%), specificity 67% (95%CI: 65-68%), positive predictive value 15% (95%CI: 10-17%), and negative predictive value 99% (95%CI: 96-100%) in ER+ cancers. The prognostic and predictive values remained significant in multivariate analysis. The same 39-gene signature was not prognostic or predictive in ER- cancers. The 30-gene signature derived from ER- tumors had no chemotherapy response predictive value in either ER- or ER+ cancers. The p53 dysfunctional cases showed better survival in the absence of any adjuvant therapy among ER- cancers. It had no prognostic value in ER+ cancers.ConclusionThese observations support the hypothesis that predictive or prognostic biomarkers may be best developed separately for different clinical and molecular subsets of breast cancer. P53 dysfunction is clinically most relevant in ER+ breast cancers.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6122.

p53 mutations to predict efficacy of alkylating-containing regimen: a metaanalysis of four different clinical trials

Abstract #6064

Background. The predictive value of p53 mutations for efficacy of anthracycline-based chemotherapy is matter of controversy. Inconsistencies among studies could be related to the heterogeneous use of alkylating agents in combination with anthracyclines in different studies. We examined the predictive value of p53 mutations in four different series of breast cancer patients treated with preoperative anthracycline-based chemotherapy including different doses of cyclophosphamide (C).
 Patients and Methods. All patients had stage II-III breast cancer and received anthracycline-containing chemotherapies. A total of 352 patients were included in four different clinical studies : 65 patients with estrogen receptor (ER)-negative cancers treated with single agent epirubicine (E) (100 mg/m2/3w x 4) in the TOP trial (R1), 52 patients treated with FAC (500 mg/m2 C, 5-FU and 50 mg/m2 doxorubicin/3w x 6) (R2), 96 patients treated with EC-T (75mg/m2 E and 750 mg/m2 C/3w x 4 followed by 100mg/m2 docetaxel/3w x 4) (R3) and 139 patients treated with dose-dense EC (1200mg/m2 C and 75 mg/m2 E/2w x 6) (R4). Before therapy, p53 status was determined in all tumors by yeast functional complementation (FASAY) assay. After chemotherapy, all patients underwent surgery. Pathologic complete response (pCR) was defined as no residual invasive tumour cells in breast and lymph nodes.
 Results. P53 mutations were more frequently observed in the 128 ER-neg compared to ER-pos cancers (78% vs 29.4%). In p53 mutated tumours, the pCR rate increased with the dose-intensity of C. Conversely, in p53 wild type tumours, pCR rates decreased.
 
 Focusing on ER-neg, p53 mutated tumors, the pCR rates rose from 11%, 6%, 32% to 52% in R1, R2, R3 and R4 groups. The R1 and R4 regimen, differing only in C dose intensity, showed marked differences in pCR in ERneg tumors.
 
 Conclusions: Increasing doses of C do not seem to improve pCR rates in P53 wild type tumours, raising the possibility of antagonism with anthracycline in this group. On the other hand, in ER-neg, p53 mutant tumors, inclusion of dose-intense C seems to significantly increase pCR rates.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 6064.

Consistent TP53 mutations in BRCA1 and sporadic basal-like breast tumors, while infrequent in luminal BRCA1 tumors

Abstract #4070

Breast tumors with a germline mutation of BRCA1 (BRCA1 tumors) and Basal-Like Carcinoma (BLC) have been shown to be associated with a high rate of TP53 mutations. Because it has also been shown that BRCA1 tumors frequently display a basal-like phenotype, we sought to determine whether TP53 mutations were correlated to the hereditary BRCA1 mutated status or to the particular histological type of these tumors. We first explored the status of the TP53 gene in a series of 28 BRCA1 BLCs using immunohistochemistry, direct sequencing of the coding sequence, and functional assay in yeast (FASAY), and compared it to the status of TP53 in 27 series of sporadic (non hereditary) BLCs. With this sensitive approach, TP53 was found consistently mutated in BRCA1 (28/28) and sporadic (26/27) BLCs. However, mutation spectrum was different, in particular with a much higher rate of insertion/deletion in BRCA1 BLCs (12/27) than in the sporadic group (2/25). Secondly, we analyzed the incidence of TP53 mutations in 10 BRCA1 luminal tumors, using the same strategy. Surprisingly, only 3 of these 10 tumors were mutated, a frequency similar to that found in matched sporadic luminal tumors. In conclusion, TP53 mutation is a mandatory event in BRCA1 or sporadic BLCs, but not a common feature of BRCA1 luminal tumors.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 4070.

[Foamy virus, an original retroviral model]

Foamy viruses (FVs) or spumaviruses are complex retroviruses isolated in several mammal species like cats, cattle and horses. Highly prevalent in non-human primates they are not naturally present in humans, although several cases of simian-to-human transmissions have been described. Interestingly, the replication strategy of FVs differs in many aspects from that of other retroviruses, presenting features that are closely related to pararetroviruses, exemplified by the hepatitis B virus (HBV), but also characteristics that are closely related to yeast retrotransposons leding to the creation of the distinct Spumaretrovirina subfamily.

[Research activities of interns in pharmacy]

During their hospital internship, French pharmacists have many opportunities to participate in research activities, especially in post-doctoral work (DEA). We conducted a national survey among pharmacy residents and interns to ascertain their motivations before completing their diploma. Many (about 50%) considered their post-doctorate work as an initiation before starting their scientific profession. Other motivations were also noted. This study provides data for future comparisons.

Two mild cystic fibrosis-associated mutations result in severe cystic fibrosis when combined in cis and reveal a residue important for cystic fibrosis transmembrane conductance regulator processing and function

The number of complex cystic fibrosis transmembrane conductance regulator (CFTR) genotypes identified as having double-mutant alleles with two mutations inherited in cis has been growing. We investigated the structure-function relationships of a severe cystic fibrosis (CF)-associated double mutant (R347H-D979A) to evaluate the contribution of each mild mutation to the phenotype. CFTR mutants expressed in HeLa cells were analyzed for protein biosynthesis and Cl(-) channel activity. Our data show that R347H is associated with mild defective Cl(-) channel activity and that the D979A defect leads to misprocessing. The mutant R347H-D979A combines both defects for a dramatic decrease in Cl(-) current. To decipher the molecular mechanism of this phenotype, single and double mutants with different charge combinations at residues 347 and 979 were constructed as charged residues were involved in this complex genotype. These studies revealed that residue 979, located in the third cytoplasmic loop, is critical for CFTR processing and Cl(-) channel activity highlighting the role of charged residues. These results have also important implications for CF, as they show that two mutations in cis can act in concert to alter dramatically CFTR function contributing to the wide phenotypic variability of CF disease.