MIB-1 Cell Membrane Reactivity: A Finding That Should be Interpreted Carefully

A simple digital image analysis system for automated Ki67 assessment in primary breast cancer

AIMS

Ki67 is a well-established immunohistochemical marker associated with cell proliferation that has prognostic and predictive value in breast cancer. Quantitative evaluation of Ki67 is traditionally performed by assessing stained tissue slides with light microscopy. Automated image analysis systems have become available and, if validated, could provide greater standardisation and improved precision of Ki67 scoring. Here, we aimed to evaluate the use of the Cognition Master Professional Suite (CogM) image analysis software, which is a simple system for scoring Ki67 in primary breast cancer samples.

METHODS AND RESULTS

Sections from 94 core-cut biopsies, 20 excision specimens and 29 pairs of core-cut biopsies and excision specimens were stained for Ki67 with MIB1 antibody and the Dako EnVision FLEX Detection System. Stained slides were scanned to convert them to digital data. Computer-based Ki67 scoring was performed with CogM. Manual Ki67 scoring assessment was conducted on previously stained sections from the same biopsies with a clinically validated system that had been calibrated against the risk of recurrence. A high correlation between manual and digital scores was observed [r_Cores  = 0.92, 95% confidence interval (CI) 0.87-0.94, P < 0.0001; r_Excisions  = 0.95, 95% CI 0.86-0.98, P < 0.0001] and there was no significant bias between them (P = 0.45). There was also a high correlation of Ki67 scores between paired core-cut biopsies and excision specimens when CogM was used (r = 0.78, 95% CI 0.59-0.89, P < 0.0001).

CONCLUSIONS

CogM image analysis allows for standardised automated Ki67 scoring that accurately replicates previously clinically validated and calibrated manual scores.

Hyalinizing trabecular tumour of the thyroid: fine-needle aspiration cytological diagnosis and correlation with histology

Hyalinizing trabecular tumour (HTT) is a rare thyroid neoplasm of follicular cell origin characterised by a trabecular growth pattern and prominent intratrabecular and intertrabecular hyalinisation. These peculiar histological features allow the prompt recognition of this neoplasm in surgical specimens. However, cytological diagnosis of HTT remains elusive and misleading because of overlapping characteristics with other thyroid tumours, particularly papillary thyroid carcinoma (PTC), medullary thyroid carcinoma (MTC) and the newly described non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP). Nevertheless, the proper recognition of this neoplasm on preoperative cytological preparations is important to avoid unnecessary overtreatment of this indolent lesion. A thorough review of the literature has revealed that the correct diagnosis of HTT in cytological smears is achieved in only 8% of cases. In a further 6% of cases, diagnostic doubt has been indicated. Sixty percent of published cases of HTT have been misdiagnosed as suggestive, suspicious or positive for PTC. These findings underline the difficulties of a cytological-based diagnosis of such entity. In this article we review the cytomorphological features of HTT and their correlation to histological features to provide the reader with the tools to improve diagnostic performance in the identification of HTT on preoperative cytology.

BGX-Ki-67 index as a supplementary marker to MIB-1 index, enabling more precise distinction between luminal A and B subtypes of breast carcinoma and eliminating the problem of membranous/cytoplasmic MIB-1 staining

OBJECTIVES

We compared clinical utility of MIB-1 and BGX-Ki-67 clones of anti-Ki-67 antibody in a group of 156 patients with invasive ductal breast cancer.

METHODS

MIB-1 labeling index (MIB-1LI) and BGX labeling index (BGXLI) were evaluated immunohistochemically both in primary tumors (T) and synchronous lymph node metastasis (LNM).

RESULTS

In addition to nuclear MIB-1 staining, in 23 of 145 and 19 of 144 T and LNM, respectively, membranous/cytoplasmic labeling was found. In these cases, BGX-Ki-67 showed exclusively nuclear labeling and presented significantly higher labeling index. High BGXLI(T) was a significant independent negative prognostic factor for disease-free survival. Moreover, based on BGXLI(T)/BGXLI(LNM), patients with high MIB-1LI(T) were stratified into low- and high-risk carriers.

CONCLUSIONS

In carcinomas with membranous/cytoplasmic MIB-1 staining, additional assessment of BGXLI is recommended. It may help in defining breast cancer subtype and in selection of individuals at risk who, despite appropriate therapy, would benefit from more frequent controls aimed at earlier implementation of second-line treatment.

[Hyalinizing trabecular tumor of the thyroid. An overcautious designation of a benign thyroid tumour?]

Hyalinizing trabecular tumours of the thyroid represent a rare entity of follicular cell derived tumours and are characterized by a marked intratrabecular hyalinisation. These tumours share architectural similarities with medullary thyroid carcinomas and exhibit nuclear features such as nuclear pseudoinclusions resembling papillary thyroid carcinoma. However, the clinical behaviour remains unclear. On the basis of their inconspicuous appearance and absence of invasion or recurrence during follow-up, the tumour was initially classified as an adenoma. Subsequently, molecular findings such as the detection of RET / PTC rearrangements in some hyalinizing trabecular tumours favoured the designation as a variant of papillary thyroid carcinoma. However, miRNA profiling of hyalinizing trabecular tumours compared with benign thyroid lesions and papillary thyroid carcinoma failed to demonstrate the characteristic up-regulation found in papillary thyroid carcinoma. This article summarizes conventional diagnostic criteria with supplementary information regarding molecular pathogenesis of hyalinizing trabecular tumours of the thyroid.

Immunohistochemical subclassification of thyroid tumors with a prominent hyalinizing trabecular pattern

The purpose of this study was to evaluate the immunohistochemical characteristics of thyroid tumors with a prominent hyalinizing trabecular pattern (TTHTP). Immunohistochemical stains for thyroid transcription factor 1 (TTF-1), thyroglobulin, CD56, cytokeratin (CK) 19, galectin-3, and Ki-67 were performed on 16 cases of TTHTP. All TTHTPs were positive for TTF-1 and thyroglobulin, and nine cases expressed CD56 and Ki-67. Of these nine cases, seven satisfied the strict criteria of Carney, and four cases were positive for CK19 or/and galectin-3 and negative for Ki-67 and CD56. The remaining three cases had no Ki-67, CD56, CK19 or galectin-3 expression. All TTHTPs meeting the criteria of Carney were hyalinizing trabecular tumors (HTT), and TTHTPs which did not satisfy the criteria of Carney were subclassified according to the immunohistochemical results as the HTT type [Ki-67 (+) and CD56 (+)], papillary thyroid carcinoma (PTC) type [CK19 or galectin-3 (+)/Ki-67 (-) and CD56 (-)], or null type [Ki-67 (-), CD56 (-), CK19 (-) and galectin-3 (-)]. TTHTPs with typical histologic features and/or with typical immunohistochemical manifestations can be categorized as HTT, and the remaining TTHTPs should be categorized as the PTC or null type.