Inter-laboratory comparison of Ki-67 proliferating index detected by visual assessment and automated digital image analysis.

BACKGROUND: Proliferation rate is a major determinant of the biologic behavior of the tumor and provides information that can be used to guide treatment decisions. METHODS: This ring study included 27 pathologists from 14 Institutions, in order to assess inter-observer concordance between pathologists in Croatia. We analyzed Ki-67 proliferative index on ten randomly selected breast cancer samples comparing consistency between visual assessment using light microscopy compared to digital image analyses results from one central laboratory as a referral value. RESULTS: When we analyzed Ki-67 as numeric value high concordance rate was found between Ki-67 score visually assessed in all participating Institutions compared to referral value assessed by digital image analysis (ICC 0.76, 95% CI 0.58-0.91), and Krippendorff's alpha was 0.79 (95% CI 0.58-1.00). Concordance was better in slides with higher Ki-67 values. When we categorized Ki-67 values according to generally accepted 20% cut-off value we noticed the lower concordance rate among participants in our study. CONCLUSION: Proliferation remains one of the most important parameters for tumor characterization helpful in making clinical decisions, but it should be used with great caution. Standardization of the Ki-67 assessment is essential and proliferating index should be expressed as exact numeric value. For patients with proliferative index near the cut-off value, other factors must be considered in making clinical decisions.

Clinicopathological Characteristics of BRAF V600E Mutated Melanomas in the Dalmatian Region of Croatia.

A high proportion of cutaneous melanomas harbor activating mutations of the BRAF or NRAS genes, which are components of mitogen-activated protein kinase (MAPK) signal transduction pathway. The importance of BRAF V600E mutation in melanoma is not only related to the possibility of the administration of the targeted therapy, but also to the fact that BRAF V600E mutated melanomas have distinct clinicopathological features. We investigated the clinicopathological features of 80 primary skin melanomas with known BRAF V600E mutation status excised in the Dalmatian region of Croatia, with comparison of these features between the mutated and wild-type group. The frequency of BRAF V600E mutation was 47.5%. In comparison with wild-type melanomas, BRAF V600E mutated melanomas were significantly associated with younger age and female sex (P=0.014 and P=0.011, respectively). The mutated melanomas were more often located on the extremities, of a nodular type, ulcerated, and with higher median of mitotic index but without significant difference in comparison with wild-type tumors. There were no differences in the depth of invasion and the presence of lymphovascular invasion, tumor infiltrating lymphocytes, and regression between the investigated groups. The frequency of BRAF V600E mutation in our cohort of primary skin melanomas and the clinicopathological features of mutated tumors were similar to those reported in the literature, except for the higher proportion of women observed in our group with mutation.

INTERLABORATORY CONCORDANCE IN HER-2 POSITIVE BREAST CANCER.

Accurate assessment of HER-2 status is essential for identifying patients who will benefit from HER-2 targeted therapy. The aim of the present study was to show results on the concordance between local and central laboratory testing results in HER-2 positive breast cancer patients. In cases with discordant findings, the immunohistochemical (IHC) and/or in situ hybridization (FISH/SISH) analysis was performed in central laboratories. A total of 104 out of 143 (72.72%) breast carcinoma cases were HER-2 positive (score 3+), while nearly 14% of tumors (20/43) showed weak (score 2+) and 12% (19/143) negative IHC staining (score 0 and 1+). After repeated IHC and ISH, 88% (126/143) were classified as HER-2 positive and 12% (17/143) as HER-2 negative cases. The results obtained are in agreement with many studies that confirmed similar discordance in HER-2 testing by IHC and/or FISH between local and central laboratory. Thus, our findings as well as those from other studies support the importance of regular quality assessment of the staining procedures performed and consistency of interpretation of HER-2 test results.

[The proportion of non-invasive (Tis) and minimal invasive cancers (T1a,b) among breast cancer in Split region]. / Zastupljenost neinvazivnih (Tis) i minimalnih invazivnih karcinoma (T1a,b) medu karcinomima dojke u splitskoj regiji.

As a result of the use of screening mammography and the introduction of programs for early detection of breast cancers, many breast biopsies are now performed for small, non-palpable, mammographically detected abnormalities. In contrast to breast biopsies in the premammographic era, breast biopsies for mammographic abnormalities contain a greater number of minimal invasive breast cancers (T1a,b), non-invasive-in situ cancers (Tis), and histological types of breast cancers with excellent prognosis. The aim of this study was to estimate the basic histopathologic features of breast cancers in Split region, with emphasis on in situ and minimal invasive cancers. The results of this study are achieved by analysis of pathohistologic characteristics of 937 breast cancers surgically removed in Split Clinical Hospital in the five year period (1997-2001), detected in population without early breast cancer detection programs. The proportion of minimal invasive cancers (T1a,b) and in situ cancers (Tis) was 15.16% and 2.78%, respectively. Axillary nodal metastases (N1) occurred in 42.9% of patients of the whole group, and in the group of minimal invasive cancers nodal metastases occurred in 14.78% of cases. The small percentage of T1a,b and Tis cases of breast cancers in Split region suggests the necessity for introduction of breast cancer early detection programs, with the emphasis on screening mammography programs in a part of female population.