The significance of combined CK5/6 and p63 immunohistochemistry in predicting the risks of subsequent carcinoma development in intraductal papilloma of the breast

Tumour 63 protein (p63) in breast pathology: biology, immunohistochemistry, diagnostic applications, and pitfalls

Tumour protein 63 (p63) is a transcription factor of the p53 gene family, encoded by the TP63 gene located at chromosome 3q28, which regulates the activity of genes involved in growth and development of the ectoderm and derived tissues. p63 protein is normally expressed in the nuclei of the basal cell layer of glandular organs, including breast, in squamous epithelium and in urothelium. p63 immunohistochemical (IHC) staining has several applications in diagnostic breast pathology. It is commonly used to demonstrate myoepithelial cells at the epithelial stromal interface to differentiate benign and in situ lesions from invasive carcinoma and to characterize and classify papillary lesions including the distinction of breast intraduct papilloma from skin hidradenoma. p63 IHC is also used to identify and profile lesions showing myoepithelial cell and/or squamous differentiation, e.g. adenomyoepithelioma, salivary gland-like tumours including adenoid cystic carcinoma, and metaplastic breast carcinoma including low-grade adenosquamous carcinoma. This article reviews the applications of p63 IHC in diagnostic breast pathology and outlines a practical approach to the diagnosis and characterization of breast lesions through the identification of normal and abnormal p63 protein expression. The biology of p63, the range of available antibodies with emphasis on staining specificity and sensitivity, and pitfalls in interpretation are also discussed. The TP63 gene in humans, which shows a specific genomic structure, resulting in either TAp63 (p63) isoform or ΔNp63 (p40) isoform. As illustrated in the figure, both isoforms contain a DNA-binding domain (Orange box) and an oligomerization domain (Grey box). TAp63 contains an N-terminal transactivation (TA) domain (Green box), while ΔNp63 has an alternative terminus (Yellow box). Antibodies against conventional pan-p63 (TP63) bind to the DNA binding domain common to both isoforms (TAp63 and p40) and does not distinguish between them. Antibodies against TAp63 bind to the N-terminal TA domain, while antibodies specific to ΔNp63 (p40) bind to the alternative terminus. Each isoform has variant isotypes (α, β, γ, δ, and ε).

Molecular phenotypes and clinical characterization of familial hereditary breast cancer among half and full sisters

Background

Preliminary clinical observations show that contemporaneous hereditary breast cancer (CHBC) patients suffered breast cancer at an early age, which requires further analysis.

Methods

38 familial hereditary breast cancer patients (18 CHBC patients and 20 non-CHBC patients) were screened out and 152 non-hereditary breast cancer patients were used as control subjects. Clinical pathologic subtypes, age, tumor location, histological grade, lymph node metastasis, and molecular phenotype expression (ER, PR, HER-2, Ki-67, CK5/6, E-cad, P63, and P120) were compared across all subgroups.

Results

The incidence of CHBC was 9.47% (18/190) in breast cancer patients. The average ages of onset of CHBC patients, non-CHBC patients, and non-hereditary breast cancer patients were 49.06 ± 6.42, 60.75 ± 9.95 and 61.69 ± 14.34 respectively; whereas there were no significant differences with respect to pathological type or tumor location. There were significant differences in some histological grading (grade II/III), lymph node metastasis and PR expression between hereditary and non-hereditary breast cancers (P < 0.05; P < 0.05 and P < 0.005, respectively). Significantly different HER-2 expression was observed when comparing all hereditary or CHBC patients with non-hereditary breast cancers (P < 0.05 and P < 0.005, respectively). There were significant differences in E-cad and P63 between contemporaneous hereditary and non-hereditary breast cancers (P < 0.005 and P < 0.05, respectively).

Conclusions

CHBC patients accounted for 9.47% (18/190) of breast cancer patients, had earlier disease onset, and showed differences compared to non-hereditary breast cancer patients with respect to molecular phenotype and clinical characteristics.

Results of Excision of Unknown Papillary Neoplasms Detected on Core Biopsy

Objective

This study aimed to find out valuable parameters that predict the nature of breast papillary lesions before excision, and we compared our results with those in the literature.

Materials and Methods

We reviewed the medical records and pathology slides of patients diagnosed with papillary neoplasm after undergoing a core-needle biopsy between 2010 and 2020, who, subsequently, underwent surgical excision in a single tertiary care institution. The core biopsy results and pathology results of excision materials were compared with the radiological, pathological, and demographic findings.

Results

A total of 51 patients were included in the study. According to the excision results, the patients were divided into two groups: the atypical group, which included 20 patients (39.3%), and the benign group, which included 31 patients (61.7%). The results of the core biopsy showed that the loss of myoepithelial cell layer was identified in 18 patients in the atypical group, while it was present in all patients in the benign group. Tumor sizes were larger and patient ages were older in the atypical group compared with the benign group. No significant difference was found between atypical and benign groups in terms of breast imaging-reporting and data system (BI-RADS) classification and location (right vs left; central vs peripheral). The upgrade rate was between 0% and 16% in literature, while it was 4% in our study.

Conclusion

There is no consensus on whether patients diagnosed with papillary neoplasia as a result of core biopsy will undergo excision. According to our results, patients with following criteria should have their lesions excised: those who are advanced in age, those who are diagnosed with a papillary lesion as a result of core biopsies with loss of myoepithelial cell layer, and those who are diagnosed with large-sized lesions without loss of myoepithelial cell layer. Patients diagnosed with small-sized lesions without loss of myoepithelial cell layer and who are young in age are to be followed up without the need for lesion excision. The lesions should be adequately sampled.

Predictive Factors for Upgrading Patients with Benign Breast Papillary Lesions Using a Core Needle Biopsy

PURPOSE

Intraductal papilloma (IDP) is a benign breast disease with malignant potential, for which complete surgical excision is usually recommended. The aim of the present study was to investigate predictive factors for upgrading patients with a benign papillary lesion (BPL).

METHODS

This study was an observational study using a prospectively collected cohort. In total, 13,049 patients who underwent a core needle biopsy (CNB) for a breast lesion between January 2009 and May 2015 were enrolled. We reviewed all patients with pathologically confirmed BPL from a CNB.

RESULTS

Surgical treatment was performed for 363 out of a total of 592 lesions. According to the pathological differences, the lowest upgrade rate was shown in IDP without atypia (without atypia, 6.0%; with atypia, 26.8%; papillary neoplasm, 31.5%; p<0.001). The univariate analysis showed that, in IDP without atypia, the age at diagnosis, size of BPL on ultrasonography, and density on mammography were associated with upgrading. The multivariate analysis revealed that age >54 years and lesion size >1 cm were significantly associated with upgrade to malignancy (odds ratio [OR]=4.351, p=0.005 and OR=4.236, p=0.001, respectively).

CONCLUSION

The indications for surgical treatment can be defined as age >54 years and mass size >1 cm, even in IDP without atypia in the CNB results; this also includes cases of IDP with atypia or papillary neoplasm. Therefore, we suggest that close observation without surgery is sufficient for younger women with a small IDP without atypia.