Prognostic value of protein tyrosine kinase 6 (PTK6) for long-term survival of breast cancer patients.

The cytoplasmic tyrosine kinase PTK6 (BRK) shows elevated expression in approximately two-thirds of primary breast tumours, and is implicated in EGF receptor-dependent signalling and epithelial tumorigenesis. Using immunohistochemistry, we performed a retrospective study on 426 archival breast cancer samples from patients with long-term follow-up and compared the protein expression levels of PTK6, the HER receptors, Sam68 (a substrate of PTK6), and signalling proteins including MAP kinase (MAPK), phosphorylated MAPK (P-MAPK), and PTEN. We show that PTK6 expression is of significant prognostic value in the outcome of breast carcinomas. In multivariate analysis, the disease-free survival of patients of >or=240 months was directly associated with the protein expression level of PTK6 (P

Accumulation of chromosomal imbalances from intraductal proliferative lesions to adjacent in situ and invasive ductal breast cancer.

Carcinoma of the breast is thought to evolve through a sequential progression from normal to proliferative epithelium and eventually into carcinoma. Here lumpectomy specimens from five patients were studied, selected for the presence of ductal hyperplasia without atypia, atypical ductal hyperplasia, ductal carcinoma in situ, and invasive ductal carcinoma. Laser microdissection of tissue allowed precise sampling and direct correlation of phenotypic and genotypic changes. Analyses of the samples revealed an increasing mean number of chromosomal changes occurring with increasing histologic severity, and for the first time chromosomal abnormalities were demonstrated in ductal hyperplasia without atypia. Chromosomal changes found in each of the four histologic entities included gains on 10q, 12q, 16p, and 20q and loss on 13q. In ductal hyperplasia without atypia, gain on 20q as well as loss on 13q was detected with high frequency (four of five samples). Alterations identified in more than 50% of atypical ductal hyperplasia samples included gains on 3p, 8q, 15q, and 22q and loss on 16q. In ductal carcinoma in situ, gain of DNA on 1q and 17q and loss on 4q were additionally found, and in invasive ductal carcinoma, further gains on 6p, 10q, 11q13, and 17p were identified. The chromosomal alterations occurring in the different histopathologic lesions strongly suggest that these regions harbor tumor suppressor genes or oncogenes significant for the development of ductal carcinoma of the breast.

PTK (protein tyrosine kinase)-6 and HER2 and 4, but not HER1 and 3 predict long-term survival in breast carcinomas.

The HER receptors are of therapeutic and prognostic significance in breast cancer, and their function is modulated by cytoplasmic tyrosine kinases like PTK6 (brk). We performed a retrospective study on archival breast cancer samples from patients with long follow-up and compared the protein expression between individual HERs and between HERs and the PTK6. Univariate and multivariate analyses were used to study the prognostic value of parameters. Metastases-free survival of patients for longer than 240 months was inversely associated (P< or =0.05) with nodal status, tumour size, and oestrogen receptor status, but was also directly associated with high protein expression levels of HER4 and PTK6 in Kaplan-Meier analysis. In multivariate analysis for metastases-free survival of >240 months, the stepwise selected parameters were tumour size (relative risk 3.1), PTK6 expression (0.4), and number of positive lymph nodes (1.2). Furthermore, we demonstrated a timedependence of the prognostic value attributed to the parameters. The HER receptors (HER2,4), but not PTK6, were independent prognostic markers for metastases-free survival at 60 months, whereas at 240 months PTK6 is the strongest prognostic marker. We demonstrate that PTK6 is a prognostic marker of metastases-free survival in breast cancer, and is independent of the classical morphological and molecular markers of lymph node involvement, tumour size, and HER2 status.

Typical and atypical carcinoid tumors of the lung are characterized by 11q deletions as detected by comparative genomic hybridization.

Neuroendocrine tumors of the lung represent a wide spectrum of phenotypically distinct entities with different biological characteristics such as typical carcinoid tumor (TC), atypical carcinoid tumor (AC), large-cell neuroendocrine carcinoma (LCNEC), and small-cell lung carcinoma (SCLC). The histogenetic relationships between TC, AC, LCNEC, and SCLC are still unclear. This study was carried out to provide cytogenetic data about pulmonary neuroendocrine tumors and to evaluate their characteristic alterations and histogenetic relations for an improved understanding of the mechanisms of tumor development. Twenty-nine paraffin-embedded tumor samples of TC (n = 17), AC (n = 6), LCNEC (n = 3), and SCLC (n = 3) were selected for isolation of tumor DNA and subsequent comparative genomic hybridization (CGH) analysis. To confirm the comparative genomic hybridization results for characteristic chromosomal imbalances, selected cases were additionally investigated by loss of heterozygosity analysis. For statistical evaluation, we also used comparative genomic hybridization data from 45 published SCLC cases. DNA underrepresentations of 11q were the most frequent findings in TC (8 of 17) and AC (4 of 6), whereas these aberrations were rare in LCNEC (1 of 3) and SCLC (0 of 3). Furthermore, AC showed DNA underrepresentation of 10q (3 of 6) and 13q (3 of 6). In contrast, SCLC and LCNEC were characterized by a different pattern of DNA losses (3p-, 4q-, 5q-, 13q-, and 15q-) and gains (5p+, 17p+, and +20). Statistical analysis revealed significantly different occurrences of 11q deletions in TC/AC versus SCLC (45 published cases of SCLC and our 3 cases; P = 0.002; Fisher's exact test). Thus, TC and AC display frequent loss of 11q material including the MEN1 gene locus, which represents a characteristic genetic alteration in these tumors. Losses of 10q and 13q sequences allow a further cytogenetic differentiation between TC and AC. These additional changes might be responsible for the more aggressive behavior of AC. Three cases of LCNEC, the first to be analyzed by comparative genomic hybridization, exhibited similar complex abnormal patterns (4q-, 5q-, 10q-, 13q-, 15q-) to those of SCLC. Although neuroendocrine tumors of the lung share common phenotypic features, suggesting a genotypic relationship, they differ remarkably in their cytogenetic characteristics, highlighting an early fundamental molecular divergence during the development of these tumors.

Chromosomal imbalances in Barrett's adenocarcinoma and the metaplasia-dysplasia-carcinoma sequence.

To characterize cytogenetic alterations found in Barrett's adenocarcinoma (BA) and, more importantly, its premalignant stages, we studied chromosomal imbalances in various lesions in the histologically proposed metaplasia-dysplasia-carcinoma sequence using comparative genomic hybridization (CGH). Using 30 esophageal adenocarcinoma resection specimens, we were able to study 30 areas of Barrett's adenocarcinoma and 8 lymph node metastases (LN). In addition, we investigated 25 premalignant lesions adjacent to BA derived from a subset of 14 resection specimens including 11 areas of high grade dysplasia (HGD), 8 areas of low grade dysplasia (LGD), and 6 areas of intestinal metaplasia (IM), which were laser-microdissected and studied with CGH. To validate the CGH findings, fluorescence in situ hybridization analysis on 13 BA with probes specific for HER-2/neu and 20q13.2 were performed. The chromosomal alterations most often identified in BA were: gains on 8q (80%), 20q (60%), 2p, 7p and 10q (47% each), 6p (37%), 15q (33%) and 17q (30%). Losses were observed predominantly on the Y-chromosome (76%), 4q (50%), 5q and 9p (43% each), 18q (40%), 7q (33%) and 14q (30%). High-level amplifications were observed on 8q23-qter, 8p12-pter, 7p11-p14, 7q21-31, 17q11-q23. Recurrent chromosomal changes were also identified in metaplastic (gains on 8q, 6p, 10q, losses on 13q, Y, 9p) and dysplastic epithelium (gains on 8q, 20q, 2p, 10q, 15q, losses on Y, 5q, 9p, 13q, 18q). Novel amplified chromosomal regions on chromosomes 2p and 10q were detected in both Barrett's adenocarcinoma and premalignant lesions. An increase of the average number of detected chromosomal imbalances from IM (7.0 +/- 1.7), to LGD (10.8 +/- 2.2), HGD (13.4 +/- 1.1), BA (13.3 +/- 1.4), and LN (22 +/- 1.2) was seen. Although the detection of common chromosomal alterations in premalignant lesions and adjacent carcinomas suggest a process of clonal expansion, the occurrence of several chromosomal changes in an apparently random order relative to one another is striking evidence that clonal evolution is more complex than would be predicted by linear models. This is probably a reflection of the existence of many divergent neoplastic subpopulations and highlights one of the main problems associated with surveillance of Barrett's patients, namely sampling error.

Molecular genetic changes in metastatic primary Barrett's adenocarcinoma and related lymph node metastases: comparison with nonmetastatic Barrett's adenocarcinoma.

Lymph node metastasis is one of the strongest negative prognostic factors for patients with Barrett's adenocarcinoma (BCA). However, despite the importance of the metastatic process in BCA, the molecular basis of it remains poorly understood. To search for cytogenetic events associated with metastasis in regional or distant lymph nodes in BCA, we investigated 8 primary BCA and their lymph node metastases and compared them with 18 nonmetastatic BCA. In metastatic primary BCA, we observed significantly more DNA gains on 3q (P = .013), 17q (P = .019), and 22q (P = .021) compared with nonmetastatic primary BCA. No statistically significant correlation could be observed between DNA copy number changes and the histopathologic stage, grade, or survival (P > .05). The most frequent alteration observed only in lymph node metastases but not in the related primary tumor was loss of 2q (5 of 8). Coamplification of 7p and chromosome 17 was found in 6 of 8 lymph node metastases. A comparison of DNA copy number changes between primary tumors and their corresponding metastases indicated a high degree of genetic heterogeneity. Fluorescence in situ hybridization analysis demonstrated the involvement of the Her-2/neu gene in primary BCA and its related lymph node metastases. Each of the investigated primary tumors and related lymph node metastases also showed striking heterogeneity with respect to Her-2/neu, with several areas displaying different levels of amplification. In summary, our data indicate that DNA copy number changes on 2q, 3q, 7p, 17q, and 22q may be involved in the metastatic process in BCA. Furthermore, the striking genetic heterogeneity that we found between primary BCA and its lymph node metastases may underlie BCA's poor responsiveness to therapy and could help explain why prognostic biomarkers measured exclusively in primary tumors give an incomplete view of the biologic potential of BCA.