Clinical and prognostic usefulness of immunohistochemical determination of Ki67 in breast cancer

Prognostic and predictive indicators in operable breast cancer

Because of its biological heterogeneity and wide spectrum of responsiveness to different treatments, breast cancer is a complex disease of difficult clinical management. Over the past several years, knowledge of the molecular mechanisms regulating normal and aberrant cell growth leading to cancer has been enhanced. These advances have enabled the identification of an increasing number of surrogate biomarkers, which have been correlated with prognosis or used as predictors of response to specific treatments. Axillary nodal status, age, tumor size, pathologic grade, and hormone receptor status are the established prognostic and/or predictive factors for selection of adjuvant treatments. The role of new biomarkers, such as p53, HER2/neu, angiogenesis, and the proliferation index value, is promising; however, the clinical value of their determination must be provided by prospective clinical studies.

Very young women (<35 years) with operable breast cancer: features of disease at presentation

BACKGROUND

Breast cancer rarely occurs in young women. Our knowledge about disease presentation, prognosis and treatment effects are largely dependent upon older series.

MATERIALS AND METHODS

We evaluated biological features and stage at presentation for 1427 consecutive premenopausal patients aged < or = 50 years with first diagnosis of invasive breast cancer referred to surgery at the European Institute of Oncology from April 1997 to August 2000. A total of 185 patients (13%) were aged < 35 years ('very young') and 1242 (87%) were aged 35-50 years ('less young'). The expression of estrogen receptors (ER), progesterone receptors (PgR), presence of vascular invasion (VI), grading (G), expression of Ki-67, HER2/neu overexpression, pathological stage according to TNM staging system (pTNM), pathological tumor size and number of axillary lymph node involvement were evaluated.

RESULTS

Compared with less young patients, the very young patient group had a higher percentage of tumors classified as ER negative (P < 0.001), PgR negative (P = 0.001), higher expression of Ki-67 > or = 20% of cells stained; 62.2% versus 53%, (P < 0.001), vascular or lymphatic invasion (48.6% versus 37.3%, P = 0.006), and pathological grade 3 (P < 0.0001). There was no difference between the two groups for pT, pathological tumor size (pN) and number of positive lymph nodes.

CONCLUSIONS

We conclude that compared with less young premenopausal patients, very young women have a greater chance of having an endocrine-unresponsive tumor, and are more likely to present with a higher grade, more extensively proliferating and vessel invading disease. Pathological tumor size, nodal status and number of positive axillary lymph-nodes have a similar distribution among the younger and the older cohorts, thus not supporting previous data indicating more advanced disease in younger patients at diagnosis of operable disease.

Prediction of response to primary chemotherapy for operable breast cancer

The use of primary systemic cytotoxics leads to a high remission rate in patients with breast cancer. Response was identified as an important variable associated with survival. Thus, features which predict response, are potentially relevant for planning treatments and improving survival. Retrospectively, we investigated several histopathological features (expression of oestrogen and progesterone receptors, Mib1, bcl-2, c-erbB-2, and p53) prior to two programmes of either sequential preoperative chemotherapy (doxorubicin plus cyclophosphamide) and radiotherapy (Group A), or preoperative chemotherapy (5-fluorouracil, folinic acid and vinorelbine) alone (Group B) in patients with operable breast cancer. After three courses, patients with a partial or complete response were given a further three courses, which was followed for patients in Group A by radiotherapy 50 Gy plus a boost of 10 Gy. All patients were submitted to surgery after completion of preoperative treatment and pathology material from 73 patients (median age, 49 years, range, 30-70; performance status, 0-1; 68 T2, 5 T3) was obtained. The overall response rate according to radiological and clinical evaluation was 59% (68% for Group A and 49% for Group B). 12 of 14 patients with p53-positive tumours and 31 of 59 with p53-negative tumours responded (P = 0.04). 6 of 7 patients with elevated c-erbB-2 had a response compared with 37 of 66 patients in the group with c-erbB-2 negative tumours (P = 0.03). Mib1 expression decreased substantially (> or = 50%) in 25 patients during treatment, of whom 20 responded compared with 21 of 48 patients with a lower decrease (P = 0.04). Response was observed in 28 of 37 patients with high baseline Mib1 (> 20%) and in 15 of 36 patients in the low Mib1 group (P = 0.05). Finally, 32 of 44 tumours with low expression of progesterone receptors responded compared with 11 of 29 tumours with high receptors expression (P = 0.05). These markers might be useful for tailoring primary and postsurgical systemic treatments.

Pre-operative chemotherapy and radiotherapy in breast cancer

Primary systemic treatment of breast cancer with cytotoxics yields a high response rate and allows conservative surgical procedures in bulky tumours. In order to maximise local control of disease, two innovations were introduced in a pilot study. The first was to identify the good responders after three cycles of chemotherapy and to treat them with three additional cycles. The second was to also give this group of patients a full dose of radiotherapy before surgery with the aim of verifying the rate of pathological complete remissions in view of a possible treatment of breast primary with chemoradiotherapy only. Patients were treated with doxorubicin 60 mg/m2 and cyclophosphamide, 600 mg/m2 both intravenously on day 1, every 21 days for three courses. Partial or complete responders received three more courses followed by radiotherapy (50 Gy plus a 10 Gy boost). The others underwent immediate surgery. A total of 32 patients (median age, 50 years; range 28-69 years); performance status, 0-1; T2 22, T3 8, T4 2) were enrolled and were evaluable for response and side-effects. 9 patients had only three cycles of chemotherapy due to absence of response and 23 patients had six cycles of chemotherapy. Overall, 7 patients had a complete remission, 16 a partial remission and 9 had stable disease, for an overall response rate of 72% (95% confidence interval 53-86%). In the group of patients that completed the programme, two complete pathological remissions were observed and 5 patients had only microfoci of tumour. No toxic death or grade III-IV toxicities were observed. Mild or moderate side-effects included mucositis, nausea/vomiting and leucopenia. In conclusion, our results indicate that the addition of radiotherapy to pre-operative chemotherapy did not significantly enhance the incidence of pathological complete remissions. New primary treatment approaches should be explored in this subset of patients in order to improve outcome.

Cytological evaluation of biological prognostic markers from primary breast carcinomas

This study was undertaken to evaluate our ability to detect multiple molecular markers of prognosis and response to treatment in fine needle aspirates (FNA) from patients with primary breast carcinomas. 147 patients with operable primary breast carcinomas who had been recruited to a randomized trial of primary medical therapy (PMT) versus adjuvant chemoendocrine therapy were analysed. FNAs were taken prior to therapy and from this multiple slides were produced using cytospin cytocentrifugation and stored at -80 degrees C for subsequent immunocytochemical analysis (ICA). ICA was performed for oestrogen receptor (ER), progesterone receptor (PgR), p53, Ki67, and Bcl-2. Part of the aspirate was snap frozen and used for flow cytometric analysis of ploidy and S-phase fraction (SPF). In a subgroup of 50 patients who had surgery prior to systemic therapy, as well as FNAs, sections were also taken from paraffin-embedded blocks and stained by ICA for ER, PgR and p53 for validation. In these patients ER was additionally measured by enzyme immunoassay (EIA) from frozen tissue taken at surgery. ER, PgR, p53, Bcl-2, and Ki67 were successfully detected by ICA while ploidy and SPF were successfully measured by flow cytometry from FNA material. The percentage positive values obtained were reasonable and as follows: 74% for ER, 70% for PgR, 36% for p53, 80% for Bcl-2,68% of tumours were aneuploid and 32% diploid. Significant relationships between these measurements were observed in accordance with expectations. The concordance for ER, PgR, and p53 from FNA when compared to ICA of matching histological sections was 91.5%, 75.5%, and 75% respectively. For ER the concordance between measurement by ICA of cytological and histological samples and by EIA of frozen tissue was 82.5% and 84% respectively. These results indicate that multiple molecular markers can be adequately tested on cytological preparations from primary breast tumours. These markers can be used to determine prognosis and predict response to PMT.

Cell kinetics in human breast cancer: comparison between the prognostic value of the cytofluorimetric S-phase fraction and that of the antibodies to Ki-67 and PCNA antigens detected by immunocytochemistry

The determination of cell proliferation is one of the more widely used tools for assessing prognosis. However, additional research in this field is warranted because today there are several methodological procedures available for monitoring cell kinetics and it has still not been established which is the most reliable marker of proliferation and which possesses the greatest prognostic value. We performed this study in a series of primary invasive breast cancers to compare the prognostic value of S-phase fraction (SPF) by flow cytometry, the most widely used method for detecting proliferation at present, with that of antibodies to Ki-67 and PC-10 to proliferating-cell nuclear antigen (PCNA) detected by immunocytochemical methods. A significant linear relationship was observed only between SPF and Ki-67. In univariate analysis SPF and Ki-67 values, nodal status, histological grading and peritumoral lymphatic-vessel invasion were significant predictors of relapse-free survival (RFS). As far as overall survival (OS) is concerned, only SPF, Ki-67 and nodal status were significantly associated with the risk of death. PCNA had no prognostic value for either RFS or OS. In multivariate analysis only SPF and nodal status retained a significant and independent prognostic value. Neither the cell-kinetics parameters assessed by immunocytochemistry (i.e. Ki-67 and PCNA) nor histological grading were independent prognosticators. In conclusion, our results provide evidence that the determination of SPF by flow cytometry was the strongest cell-kinetics marker used to assess prognosis in this series of breast cancers. However, different and novel markers of cell kinetics need to be compared in larger series in order to identify the best one.