Cytomorphology as a risk predictor: experience with fine needle aspiration biopsy, nipple fluid aspiration, and ductal lavage

The potential of identification of a malignancy-associated biomarker in breast cancer diagnosis and research: hTERT gene DNA methylation

BACKGROUND

DNA hypermethylation has been documented to be prominent at a CpG island rich region about 600 bp upstream the transcription start site of the hTERT gene using qualitative methylation specific PCR on DNA isolated from tumor cell lines. In order to assess the potential significance of this biomarker in breast cancer research and diagnosis, we explored if such findings are reproducible on surgically resected fresh breast tumor cells.

METHODS

Using quantitative pyrosequencing technology, we investigated and present methylation status of four CpG islands of this region in a cohort of 77 invasive breast carcinomas using normal breast tissue as controls.

RESULTS

Globally, a significant hypermethylation in tumor cells was observed in the four CpG islands as a sum, in comparison to methylation of the normal breast tissue. Individually, certain CpG islands displayed methylation greater than 50% in about 3/4 of the 77 breast cancers, but in none of the normal breast tissue. Our results highlight the value of DNA hypermethylation in the -600 bp region of the hTERT gene as a potential marker for breast cancer diagnosis.

CONCLUSIONS

We believe that integration of this novel, malignancy-associated molecular testing with morphology is of significant value in the accurate interpretation of small tumor sample size obtained via fine needle aspiration biopsy, ductal lavage, and nipple fluid aspirates both in clinical practice and in breast cancer research. Diagn. Cytopathol. 2016;44:670-675. © 2016 Wiley Periodicals, Inc.

MicroRNA analysis of breast ductal fluid in breast cancer patients

Recent studies suggest that microRNAs show promise as excellent biomarkers for breast cancer; however there is still a high degree of variability between studies making the findings difficult to interpret. In addition to blood, ductal lavage (DL) and nipple aspirate fluids represent an excellent opportunity for biomarker detection because they can be obtained in a less invasive manner than biopsies and circumvent the limitations of evaluating blood biomarkers with regards to tissue of origin specificity. In this study, we have investigated for the first time, through a real-time PCR array, the expression of 742 miRNAs in the ductal lavage fluid collected from 22 women with unilateral breast tumors. We identified 17 differentially expressed miRNAs between tumor and paired normal samples from patients with ductal breast carcinoma. Most of these miRNAs have various roles in breast cancer tumorigenesis, invasion and metastasis, therapeutic response, or are associated with several clinical and pathological characteristics of breast tumors. Moreover, some miRNAs were also detected in other biological fluids of breast cancer patients such as serum (miR-23b, -133b, -181a, 338-3p, -625), plasma (miR-200a), and breast milk (miR-181a). A systems biology analysis of these differentially expressed miRNAs points out possible pathways and cellular processes previously described as having an important role in breast cancer such as Wnt, ErbB, MAPK, TGF-β, mTOR, PI3K-Akt, p53 signaling pathways. We also observed a difference in the miRNA expression with respect to the histological type of the tumors. In conclusion, our findings suggest that miRNA analysis of breast ductal fluid is feasible and potentially very useful for the detection of breast cancer.

Development of a novel approach for breast cancer prediction and early detection using minimally invasive procedures and molecular analysis: how cytomorphology became a breast cancer risk predictor

With enhanced public awareness, advances in breast imaging, and emphasis on early breast cancer detection and prevention, more women are seeking consultation to assess the status of their breast health. Risk assessment has become an integral part of established multi-disciplinary breast care, and breast cancer risk reduction interventions have received a great deal of attention. Similarly, interest in identification of high-risk individuals has increased significantly. Atypical proliferative changes in breast epithelial cells are ranked high among various known breast cancer risk factors and, in recent years, have been the subject of several investigations. Breast tissue and fluid in the ductal system provide a rich source of cells and biomarkers that have the potential to aid in the assessment of short-term risk of breast cancer development, and assess responses to interventional prevention efforts. There are three minimally invasive procedures currently being utilized to sample breast tissue in asymptomatic high-risk individuals. These procedures are: fine-needle aspiration biopsy, nipple aspiration fluid, and ductal lavage. In this review article, the merits and limitations of each procedure are presented, and the contribution of cytomorphology and molecular analysis in breast cancer prediction is highlighted. In addition, the role of Masood Cytology Index as a surrogate endpoint biomarker in chemopreventative trials is discussed.

Unraveling breast cancer heterogeneity through transcriptomic and epigenomic analysis

Breast cancer diversity is histologically evident as various proliferative benign lesions, in situ carcinomas, and invasive carcinomas that may develop into distant metastases. Breast tumor molecular subtypes have been defined by genome-wide expression microarray technology and reveal associations between genetic alterations and the malignant phenotype. Early work has been conducted to use subtype-specific biomarkers to elucidate targeted treatment options early in the course of breast cancer progression. Additionally, DNA methylation is an epigenetic modification that contributes to breast cancer progression by transcriptionally silencing certain tumor suppressor genes. Among the genes characterized as targets for silencing are well-established tumor suppressors such as RASSF1A, RARB, SFN, and TGM2. Measuring elevated gene copy number and aberrant gene promoter methylation can further facilitate characterization of breast tumor molecular subtype; however, profiling of breast tumors based on epigenetic criteria has yet to be established. Epigenomic analysis has been investigated for clinical applicability, and it has great promise when used in combination with minimally invasive techniques for both diagnostic and prognostic purposes.

Fine needle aspiration for evaluation of breast masses

PURPOSE OF REVIEW

Fine needle aspiration has been used for many years as a diagnostic tool for breast lesions, with high sensitivity and specificity. There is controversy as to whether this technique should be replaced by other diagnostic procedures such as core biopsy. This review aims to re-evaluate the usefulness of breast fine needle aspiration.

RECENT FINDINGS

During the past 10 years many institutions have replaced fine needle aspiration by core biopsy and related techniques such as vacuum-assisted core biopsy and advanced breast biopsy instrument action. Other institutions continue to use fine needle aspiration as a first line of investigation for breast lesions. This technique is especially useful in radiologically benign lesions and when combined with image guidance. The use of the 'triple test' (combined cytologic, clinical and radiologic findings) decreases false-negative and false-positive results.

SUMMARY

Fine needle aspiration continues to be an acceptable and reliable procedure for the preoperative diagnosis of breast lesions, particularly in developing countries, and when used as part of the 'triple test'. Accurate diagnosis requires experience in both aspiration technique and specimen interpretation. Clinicians should be mindful of the limitations of the technique. The choice between fine needle aspiration and core biopsy should be individualized for the patient.