Quantitative real-time PCR analysis and microarray-based RNA expression of HER2 in relation to outcome.

BACKGROUND: Our aim was to use quantitative real-time PCR (Q-PCR) and RNA expression profiles (RNA-EPs) to investigate HER2 status in relation to outcome. PATIENTS AND METHODS: Cut-off levels for Q-PCR and RNA-EP were established in relation to immunohistochemistry (IHC) validated by FISH in a test set of frozen tissue samples from 40 primary breast cancers. The HER2 status was subsequently studied in another validation set of 306 tumors, where Q-PCR and RNA-EP results were compared with previously carried out IHC that we had validated by chromogenic in situ hybridization (CISH). RESULTS: Q-PCR and RNA-EP offered similar sensitivity (90% versus 77%), specificity (93% versus 95%), and negative (99% versus 98%) and positive (63% versus 61%) predictive values for HER2 determinations. Analyses of relapse-free survival (RFS) and overall survival on the basis of 5 and 10 years of follow-up indicated equivalent hazard ratios for all three techniques. In contrast to IHC/CISH, both Q-PCR and RNA-EP analyses of HER2 also gave statistically significant results regarding RFS and breast cancer-corrected survival after 10 years of follow-up. CONCLUSION: The use of RNA-EP and Q-PCR to analyze HER2 in frozen and formalin-fixed breast cancer samples may be an alternate approach to IHC in combination with FISH/CISH.

Worse survival for TP53 (p53)-mutated breast cancer patients receiving adjuvant CMF.

BACKGROUND: TP53 has been described as a prognostic factor in many malignancies, including breast cancer. Whether it also might be a predictive factor with reference to chemo- and endocrine therapy is more controversial. PATIENTS AND METHODS: We investigated relapse-free (RFS), breast cancer-corrected (BCCS) and overall survival (OS) related to TP53 status in node-positive breast cancer patients that had received polychemotherapy [cyclophosphamide, methotrexate, 5-fluorouracil (CMF)] and/or endocrine therapy (tamoxifen). Sequence analyses of the whole TP53 coding region was performed in 376 patients operated on for primary breast cancer with axillary lymph node metastases between 1984 and 1989 (median follow-up time 84 months). RESULTS: TP53 mutations were found in 105 patients (28%). We found 90 (82%) of the 110 mutations in the more frequently analysed exons 5-8, while the other 20 (18%) were located in exons 3-4 and 9-10, respectively. Univariate analyses showed TP53 to be a significant prognostic factor with regard to RFS, BCCS and OS in patients who received adjuvant CMF. CONCLUSIONS: TP53 mutations might induce resistance to certain modalities of breast cancer therapy. Sequence-determined TP53 mutation was of negative prognostic value in the total patient population and in the CMF treated patients.

Increased p53 mutation frequency during tumor progression--results from a breast cancer cohort.

The mutational patterns of the p53 gene for exons 4-9 were analyzed in 30 recurring tumors compared with the p53 status of the corresponding 30 primary breast cancers. The prevalence of p53 mutations was higher, although not statistically significant (P = 0.07), in the evaluable recurring tumors compared with the corresponding primaries, 12 of 29 (41%) versus 7 of 30 (23%). Twenty-one of the patients had unchanged p53 mutation status in the recurring compared with the primary tumors, whereas 8 had an altered mutational status or pattern in the sequential tumor. These findings indicate that p53 mutations may be an important factor for tumor progression in human breast cancer.

Enzymatic mutation detection method evaluated for detection of p53 mutations in cDNA from breast cancers.

BACKGROUND: Rapid, reproducible, and easily run methods with high sensitivity and specificity are required for mutation screening of clinical samples. We evaluated the Enzymatic Mutation Detection (EMD(TM)) method by analysis of archival cDNA from 203 breast cancer patients and comparison with results of cDNA-based sequencing of the tumor suppressor gene p53. METHODS: The EMD technology uses the T4 endonuclease VII, which cleaves double-stranded DNA at sites where a DNA mismatch is present because of mispairing or an insertion/deletion of nucleotides. The EMD analyses were carried out by dividing the p53 gene into two overlapping fragments that were analyzed separately. After PCR amplification, the fragments were hybridized with wild-type p53 and subsequently exposed to the EMD enzyme. Cleavage products were analyzed and scored using an ALF(TM) automated DNA sequencer and ALFwin Fragment Analyzer software (VER: 1.02). RESULTS: The EMD technique had sensitivities of 45% and 64% and specificities of 83% and 84% for the two fragments, respectively. Patients with EMD-positive, wild-type p53 tumors had a survival similar to that of patients with EMD-negative, wild-type p53 tumors. Node-positive patients with p53 mutated tumors according to sequencing had a statistically significantly worse overall survival than those with p53 wild-type tumors (P = 0.016), whereas this difference in survival was not detected when p53 status was determined with EMD (P = 0.47). CONCLUSIONS: EMD had insufficient sensitivity for consideration in screening for the p53 gene in this archival material. Sequencing must still be considered as the standard procedure.

The expression of vascular endothelial growth factor correlates with mutant p53 and poor prognosis in human breast cancer.

Wild-type p53 protein has been shown to inhibit angiogenesis through thrombospondin in the preclinical setting. Here, we determined the associations between the expression of the angiogenic factor vascular endothelial growth factor (VEGF) and the p53 status, including different mutation sites and types, in primary breast cancer. Cytosols from 224 primary breast cancer patients were analyzed with an enzyme immunoassay for determination of human VEGF165 protein content. p53 status was determined by cDNA-based sequencing of the entire coding region, by immunohistochemistry (IHC), and by a p53 luminometric immunoassay (LIA) method. Statistically significant associations was found between higher VEGF content and non-wild-type p53 status for all methods; sequence-based data (P = 0.0019), IHC data (P = 0.0068), and the LIA method (r = 0.427; P > 0.001). Highest VEGF values were detected in tumors with p53 insertions, deletions, and stop codon mutations (P = 0.0043). Combining p53 status and VEGF content resulted in additional prognostic information, relapse-free survival (RFS; P = 0.0377), overall survival (OS; P = 0.0319), and breast cancer corrected survival (BCCS; P = 0.0292). In multivariate analysis, the relative hazard increased when the VEGF data were added to the p53 status, with a relative hazard of 1.7 for RFS and 3.0 for BCCS, compared with 1.1 for RFS and 1.4 for BCCS among the patients with either high VEGF content or p53 mutation. Higher VEGF content was statistically significantly correlated with a worse outcome for patients with estrogen receptor-positive tumors receiving adjuvant tamoxifen: RFS (P = 0.0471), OS (P = 0.0134), BCCS (P = 0.0064), as well as in multivariate analysis with point estimates of 3.4 and 2.1 for BCCS and RFS, respectively. VEGF expression is related to p53 status in human breast cancer patients. Combining VEGF with p53 status resulted in better prognostic prediction.

Can axillary dissection be avoided by improved molecular biological diagnosis?

Axillary dissection is presently a routine staging procedure in the management of breast cancer. The use of adjuvant systemic treatment is largely based on the diagnosis of axillary metastases. Routine axillary dissection leads to acute and chronic side-effects in a large proportion of patients. The sentinel node technique is presently explored with the aim of decreasing the need for standard axillary dissection. A complementary way forward is to analyse the primary breast cancer for molecular markers with prognostic significance with reference to the risk for metastatic capacity and thereby obtain a 'biological staging' and identify those patients in need of systemic adjuvant therapy. A large number of molecular biological factors have been shown to have prognostic significance in breast cancer e.g. c-erbB-2, p53, uPA, PAI-I and VEGF. This article reviews the expression of these and other factors in the primary breast cancers in relation to the risk for axillary and systemic metastatic disease, with the long-term aim of excluding routine axillary dissection.