Association of the polymorphisms CYP19 (TTTA)n in treatment response to hormone therapy based in aromatase inhibitors in breast cancer patients

Abstract #3033

Background 
 Case-control studies have reported inconsistent results concerning breast cancer risk and polymorphisms in genes that control endogenous estrogen biosynthesis. We report findings from the first study in Mexican women examining associations between female with breast cancer and polymorphisms CYP19 (TTTA repeated polymorphism).
 Methods 
 We conducted a study among 180 healthy women and 70 women with breast cancer underwent hormone therapy with aromatase inhibitor. DNA and questionnaire data was obtained. Tandem repeated (TTTA)n polymorphism in CYP19 gene was determined by PCR followed by electrophoresis on denaturalizing acrilamide gel stained with silver nitrate. Differences were visualized with Gel-Doc BioRad. Estrone, estradiol and FSH levels were measured by RIA and IRMA. We used likelihood-based statistical methods to examine allelic associations.
 Results:
 250 women (age 55 ± 12 years) were included. BMI was 30 ± 7.1 Kg/m2. We found a distribution of different CYP19 allele frequencies. In healthy women the allele frequencies with 6 (32.7 %) and 7 (21.6 %) tandem repetitions were the most frequent, in women with breast cancer the alleles with 6(29%) and 10(26%) tandem repeated were the most frequent. A relationship between hormonal levels and number of (TTTA) repeated was not found. Anastrozol reduced significantly estrona and estradiol. Surpriseling we found in a patients with 10 or more (TTTA)n repeated an association with a mayor tumoral activity (p=0.04).
 Conclusion 
 This study indicates that status of CYP19 >10 TTTA repeated might be related to increased breast cancer risk and with the clinical response (aromatase inhibitor). Because of this is the first study to report an association between CYP19 >10 TTTA repeated and treatment hormonal response in breast cancer.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3033.

Biomarker analysis by tissue microarray technology of Bik, Bcl-2, Bax, ER-α, ER-β, Her2/neu, PCNA, P53, pRB proteins and apoptotic index (by TUNEL) in breast cancer Mexican biopsies

Abstract #4043

Background: 
 The development and progression of epithelial cancers are the results of changes in many genetic networks. Through massive analysis techniques various prognostic factors have been studied to determine proteins implicated in cancer. A new technology used is tissue microarray (TMAs), which allows the assessment of several patients at different stages in a single slide.
 Methods:
 TMA blocks with up to 128 cylinders were made by using 1.5-mm diameter tissue cores from each paraffin block. In a series of 70 formalin-fixed carcinomas, we analyzed the immuno-expression of Bik, Bcl-2, Bax, ER-α, ER-β, Her2, PCNA, P53 and RB proteins. For apoptosis detection the TUNEL technique was used. Expression profiles for these tumors were generated with an unsupervised clustering and a T Test analysis.
 Results:
 We developed TMAs with samples from Mexican women with breast cancer at different stages (type I, II and III) and compared these with those of non affected breast tissue of the same women's samples. Through a hierarchical cluster we found three subgroups of tumors according to protein expression behavior. The apoptotic process was found in low grade 4.28%; moderate grade 90% and high grade 5.71% of samples. Statistical analysis revealed that Bax gene (p=0.000) expression was significantly increased in samples stage I and underexpressed in samples stage IIIA. The Bcl-2 gene was under-expressed in the majority of samples of the stage II. Even when the Bik gene was detected the protein level was over-expressed in 44.29% of the cases with noa significant correlation with apoptosis (TUNEL) (p=0.006). The samples where there were more alterations of the studied proteins were understood in the stages IIA (T2N0M0) and IIB (T2N1M0).
 
 Conclusions:
 The analysis of specimens of several patients in different stages of the disease turns out to be useful to establish a better diagnosis and prognosis. Differential regulation of these genes, especially Bik and Bax, may contribute to the biological nature of a clinically more aggressive and highly proliferative breast cancers.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 4043.

Expression of telomerase enzyme as predictive factor of response to first line chemotherapy with gemcitabine/carboplatin in advanced non-small cell lung cancer (IIIB and IV)

17156

Background: Non-small cell lung cancer (NSCLC) is the most frequent neoplasia in the world and the main cause of death for cancer. The palliative chemotherapy is the elected treatment for patients in stage III and IV. The telomerase enzyme is expressed in 82% of neoplasias and its activity is implied in the genomic instability, apoptosis inhibition and cell immortalization. Objective: To determine the predictive value of the expression of the telomerase enzyme with the first line regimen gemcitabine (1 gr/m2 SC, days 1 and 8) and carboplatino (AUC of 5 in day 1) every 28 days in patients with NSCLC clinical stages IIIB and IV. The response and toxicity rate was also determined. Methods: Patients were recruited in a period between 04/01/2004 and 11/30/2004, ages between 18 and 80, ECOG ≤ 2, measured disease (RECIST), virgin to treatment, permissible hematic biometry for chemotherapy and optimal kidney function. A total of 17 patients with an average age of 61 (range 44 to 77 years old) 9/17 (53%) males and 8/17 (47%) females, 4/17 with clinical stage IV (23%) and 13/17 with clinical stage IIIB (77%) from which: 8/13 (61%) presented pleural effusion. From the total number of patients, 1/17 presented ECOG 0 (6%), 14/17 ECOG 1 (82%) and 2/17 ECOG 2 (12%). The histopathologic diagnosis was adenocarcinoma in 12/17 (70%) and epidermoid carcinoma in 5/17 (30%). A rabbit polyclonal antibody was used to asses the expression of the telomerase enzyme by the immunohistochemical method. Results and Conclusions: It was demonstrated in 11/17 patients that the high expression of telomerase enzyme is directly correlated to the lack of response to treatment (3/11 patients stable disease and 4/11 with progressive disease); and a low or absent expression (4/11 patients) was correlated to a response higher than 30% (p = 0.045). The obtained response rate was lower that the previous ones reported with the regimen gemcitabine (days 1, 8 every 21 days and 1, 8 and 15 every 28 days) presenting a minimum hematologic toxicity. This analysis suggests that the telomerase enzyme could be a response predictive marker in the NSCLC with this therapeutic regimen.

No significant financial relationships to disclose.