Correlation of p53 mutations in ThinPrep-processed fine needle breast aspirates with surgically resected breast cancers

The role of ThinPrep cytology in the evaluation of estrogen and progesterone receptor content of breast tumors

INTRODUCTION

The objective of the current study was to analyze the potential value of immunocytochemical analysis on ThinPrep (TP)-processed smears, from fine needle aspiration (FNA) biopsies, of breast tumors for the determination of ER and PR content as compared with the immunohistochemical analysis performed on paraffin-embedded breast tumor specimens.

PATIENTS AND METHODS

Percutaneous FNA biopsy of focal breast lesions in 119 female adult patients during a 31-month period was performed. Subsequently, these patients underwent surgical resection of the tumors. ER and PR status of the tumors was determined by immunocytochemical analysis on TP-processed smears and by immunohistochemical studies in paraffin-embedded sections.

RESULTS

With the use of TP technique adequate material was observed in all cases. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and overall accuracy (OA) of the TP technique for the ER were 98.95%, 100%, 100%, 95.84% and 99.15% respectively. In addition, sensitivity, specificity, PPV, NPV and OA of the TP technique for the PR were 100%, 87.5%, 95.60%, 100% and 96.64%, respectively.

CONCLUSIONS

ER and PR status can be evaluated in FNA material from breast carcinomas by using the TP technique. Sample collection and storage is simple and permits the assortment of the FNA sample for both morphologic diagnosis and ancillary studies. The accuracy of TP technique in the detection of ER and PR content is comparable to those of the histological evaluation, and could be of paramount importance for the preoperative planning of treatment.

Non-gynecologic cytology on liquid-based preparations: A morphologic review of facts and artifacts

Liquid-based preparations (LBP) are increasingly being used both for gynecologic (gyn) and non-gynecologic (non-gyn) cytology including fine needle aspirations (FNA). The two FDA-approved LBP currently in use include ThinPrep (TP), (Cytyc Corp, Marlborough, MA) and SurePath (SP), (TriPath Imaging Inc., Burlington, NC). TP was approved for cervico-vaginal (Pap test) cytology in 1996 and SP in 1999 and both have since also been used for non-gyn cytology. In the LBP, instead of being smeared, cells are rinsed into a liquid preservative collection medium and processed on automated devices. Even after a decade of use, the morphological interpretation of LBP remains a diagnostic challenge because of somewhat altered morphology and artifacts or facts resulting from the fixation and processing techniques. These changes include cleaner background with altered or reduced background and extracellular elements; architectural changes such as smaller cell clusters and sheets, breakage of papillae; altered cell distribution with more dyscohesion and changes in cellular morphology with enhanced nuclear features, smaller cell size and slightly more three-dimensional (3-D) clusters. Herein, we review the published literature on morphological aspects of LBP for non-gyn cytology.

p53 Alterations and protein accumulation in benign breast tissue and breast cancer risk: a cohort study

Disruption of p53 gene function seems to have a pivotal role in carcinogenesis. p53 gene changes occur before the development of breast cancer and therefore might influence breast cancer risk. We investigated the association between p53 protein accumulation and p53 mutations detected in benign breast tissue and risk of subsequent breast cancer. We conducted a case-control study nested within the cohort of 4,888 women in the Canadian National Breast Screening Study who were diagnosed with biopsy-confirmed benign breast disease during active follow-up. Cases were women with benign breast disease who subsequently developed breast cancer; five controls were matched to each case. p53 protein accumulation was assessed immunohistochemically using sections of paraffin-embedded benign breast tissue from 104 cases and 385 controls; for 82 of these cases and 327 of the controls, DNA was successfully extracted from the breast tissue for p53 gene analysis using PCR-single-strand conformation polymorphism/direct sequencing. p53 protein accumulation was associated with a 2-fold increase in risk of progression to breast cancer [adjusted odds ratio (OR), 2.16; 95% confidence interval (95% CI), 1.08-4.30], whereas p53 nucleotide changes overall were not associated with altered risk (adjusted OR, 1.22; 95% CI, 0.68-2.19); those with both p53 immunopositivity and a p53 nucleotide change had an OR (95% CI) of 3.20 (1.21-8.50). Nonpolymorphic intronic changes were associated with a 2.8-fold increase in risk (OR, 2.84; 95% CI, 1.09-7.41). The results of this study suggest that p53 protein accumulation and nonpolymorphic intronic changes in p53 are associated with increased risk of progression to breast cancer in women with benign breast disease.

The role of liquid-based cytology in the investigation of breast lesions using fine-needle aspiration: A cytohistopathological evaluation

INTRODUCTION

Liquid-based cytology processing of breast fine-needle aspiration (FNA) specimens has been used in our institution since 1999. The aim of this study was to investigate the role of liquid-based cytology (Thin-Prep(R)) in the evaluation of breast FNA specimens.

PATIENTS AND METHODS

This study was carried out on 352 cases corresponding to equal number of women (134 malignant and 218 benign) examined from September 1999 to June 2003. A direct to vial study was planned. Aspirated material was directly immersed to cytolytR vial (Cytyc Corporation, Boxborough, MA). The specimens were transported to the laboratory non-refrigerated within 24 hr. Thin-Prep slides were made using the Thin-Prep 2000 processor. The remaining material was embedded in paraffin.

RESULTS

Altogether, 352 cases were examined and unsatisfactory smears were observed in 14 (3.9 %) out of all cases. The histologic examination verified that 128 out of 131 total malignant cases and 203 out of 207 total benign cases were correctly diagnosed with the cytological technique. False positives were found in four cases and false negative in three cases. Liquid-based technique presented a sensitivity of 97.7%, a specificity of 98%, a positive predictive value (PPV) of 96.9%, a PNV of 98.5%, and an over all accuracy (OA) of 97.9%.

CONCLUSIONS

The processing of FNA breast specimens using liquid-based cytology offers an accurate diagnostic tool. Liquid-based cytology could reduce the uncertainty based in the cytological evaluation of FNA, because it offers the possibility to embed material in paraffin and take tissue sections with histological appearance identical to those observed in routine histological sections. Moreover it offers the potential advantage of retraining extra material for the purpose of ploidy analysis and immunohistochemical study in order to offer information concerning the expression of prognostic markers such as p53, MIB-1, steroid hormone receptors, and EGFR.

Evaluation of Oligonucleotide Arrays for Sequencing of the p53 Gene in DNA from Formalin-Fixed, Paraffin-Embedded Breast Cancer Specimens

Background: Routine tissue processing has generated banks of paraffin-embedded tissue that could be used in retrospective cohort studies to study the molecular changes that occur during cancer development. The purpose of this study was to determine whether a p53 microarray could be used to sequence the p53 gene in DNA extracted from formalin-fixed, paraffin-embedded (FFPE) tissues.

Methods: DNA was extracted from 70 FFPE breast cancer tissue specimens. p53 was sequenced with an oligonucleotide microarray (p53 GeneChip®; Affymetrix), and the results were compared with the results obtained from direct sequencing.

Results: DNA was extracted from 62 of 70 cases. We identified 26 mutations in 24 of the 62 cases by the p53 GeneChip. No polymorphisms were detected, and exon 4 could not be evaluated in 20 cases. There were 43 genetic alterations detected by direct sequencing in 35 of the 62 cases. These consisted of 26 polymorphisms and 17 mutations in exons or splice sites. Fifteen mutations were identified by both methods. Direct sequencing detected significantly more gene alterations (43 of 54) in DNA extracted from FFPE tissue than the p53 GeneChip (26 of 54; P = 0.018). However, if the changes in exon 4 were eliminated from this comparison, the p53 GeneChip detected 26 of 27 mutations compared with direct sequencing, which identified 16 of 27 mutations. (P = 0.016).

Conclusions: A combination of oligonucleotide microarray and direct sequencing may be necessary to accurately identify p53 gene alterations in FFPE breast cancer. The p53 GeneChip cannot be used to detect exon 4 polymorphisms (codon 72) in FFPE breast cancer tissue.

ThinPrep-processed fine-needle samples of breast are effective material for RNA- and DNA-based molecular diagnosis: application to p53 mutation analysis

BACKGROUND

Fine-needle sampling is the least invasive method of in vivo breast carcinoma sampling and can provide material for breast carcinoma diagnosis. The aim of the current study was to assess the accuracy of molecular diagnosis techniques using fine-needle sample (FNS) material stored in PreservCyt (Cytyc Corp., Boxborough, MA).

METHODS

The p53 tumor suppressor gene was chosen as a model because it can be used for DNA, RNA, and protein analysis. Molecular analysis was performed using a yeast functional assay and DNA sequencing. p53 accumulation was evaluated by immunocytochemistry.

RESULTS

DNA and protein analysis indicated that samples stored for periods of several months, either at room temperature, 4 degrees C, or -20 degrees C, can be processed reliably. For RNA-based diagnosis, samples were still intact after 5 months of storage in PreservCyt at 4 degrees C. In addition, using FNS material that was stored for 16 months at 4 degrees C, the authors detected p53 mutations with either the functional assay for separating alleles in yeast (an RNA-based functional assay) or direct cDNA sequencing.

CONCLUSIONS

Fine-needle samples stored in PreservCyt at 4 degrees C are very good material for molecular diagnosis techniques. In addition, it is feasible to adopt a strategy of storing excess FNS material to create cellular banks that will be invaluable for future gene studies.

HOPE--a new fixing technique enables preservation and extraction of high molecular weight DNA and RNA of > 20 kb from paraffin-embedded tissues. Hepes-Glutamic acid buffer mediated Organic solvent Protection Effect

The growing number of molecular pathologic tools that are currently available require material with good long term preservation of morphology, nucleic acids, and antigenic structures. However, pathologic investigations of tissues done at a molecular level are often hampered by the fixatives in use. We thus endeavored to design a new fixing system, including subsequent paraffin-embedding and sectioning, that makes complete pathologic analyses possible, with special consideration of immunohistochemistry (IHC), in situ hybridization (ISH), and molecular pathology. The optimized HOPE (Hepes-Glutamic acid buffer mediated Organic solvent Protection Effect) fixing technique allows us to preserve and extract high molecular weight DNA and RNA of > 20 kbp suitable for downstream applications, such as PCR and RT-PCR from HOPE-fixed, paraffin-embedded tissues that are up to 5 years old. This technique will most probably lead to new impacts on molecular pathology.