Immunocytochemical double staining of cytokeratin and prostate specific antigen in individual prostatic tumour cells

Immunocytologic detection of isolated tumor cells in bone marrow of patients with squamous cell carcinomas of the head and neck region

The well-documented specificity of anticytokeratin monoclonal antibodies for detection of epithelial micrometastatic cancer cells in bone marrow as a prognostic indicator inspired us to apply this approach to patients with squamous cell carcinomas (SSC) of the head and neck region. The sensitivity of the broad-spectrum anticytokeratin monoclonal antibody (mAb) A45-B/B3 used for tumor cell detection was demonstrated by immunostaining of cryostat sections from the respective primary tumors. Analysis of 31 patients with SSC revealed A45-B/B3-positive cells in 10 cases (32.3%) at frequencies of 1-207 per 1 x 10(6) mononuclear cells. Most specimens displayed isolated tumor cells, while cell clusters were found in only two cases (6.5%). The present data suggest that hematogenous dissemination of cancer cells is more frequent than expected from clinicopathologic staging of patients with SSC of the head and neck region.

Immunocytochemical detection of isolated tumour cells in bone marrow of patients with untreated stage C prostatic cancer

The micrometastatic spread of tumour cells is usually missed by conventional diagnostic techniques, although this spread largely determines the prognosis of patients with primary epithelial cancers. By use of the monoclonal antibody, CK2, to epithelial cytokeratin component number 18 (CK18), individual disseminated carcinoma cells present in bone marrow of cancer patients can now be identified. In the present study, this approach has been applied to patients with virginal stage C adenocarcinoma of the prostate. Double-sided aspirates of iliac bone marrow from 24 of 44 evaluable patients (54.4%) exhibited between one and 38 CK18-positive cells per sample of 2 x 10(6) mononuclear cells. In 13 of these 24 positive patients, CK-positive cells were only detected in one of the two aspirates analysed. There was no statistically significant correlation between this finding and established risk factors, such as the volume and histological grade of the primary tumour or the concentration of prostate specific antigen and prostatic acid phosphatase in serum. The follow-up time is too short to provide meaningful data on the prognostic significance of isolated CK18-positive cells in bone marrow, which, however, has been recently demonstrated in other types of primary epithelial cancers. In conclusion, the presence of prostatic tumour cells in bone marrow might be interpreted as an indicator of the metastatic capacity of an individual primary tumour. The immunocytochemical detection of these cells may, therefore, be useful for increasing the precision of current tumour staging, and to monitor minimal residual cancer in an individual patient.

Immunocytological detection of micrometastatic cells: comparative evaluation of findings in the peritoneal cavity and the bone marrow of gastric, colorectal and pancreatic cancer patients

The prognosis of digestive cancers is poor mainly due to intraperitoneal relapse by cells which may have already been seeded at the time of surgery. Using immunocytology we investigated the peritoneal cavity and, as a comparison, the bone marrow of 147 patients with gastric, colorectal and pancreatic cancer for micrometastatic cells. Cytological samples from peritoneal cavity lavages and bone marrow aspirates were analyzed using monoclonal antibodies (MAbs) against tumor-associated antigens (TAA) (CEA, CA-19-9, 17-1-A, C-54-0, Ra96) and compared to a MAb staining cytokeratins (KL-1). Patients with benign diseases served as controls. Intraperitoneal micrometastatic cells were detected in 27% of colorectal, 43% of gastric and 58% of pancreatic cancer patients. In the bone marrow, the corresponding data were 29% for colorectal, 25% for gastric and 58% for pancreatic cancer patients. Combined evaluation of both compartments increased the detection rate significantly (colorectal cancer: 40%, gastric cancer: 52%, pancreatic cancer: 72%). No unwarranted reactions were found in the control group. Combining 3 antibodies (CA-19-9, Ra96, C-54-0) enabled good detection for peritoneal cavity samples. In the bone marrow, the use of 2 antibodies (KL-1 and CA-19-9) detected 94% of all positive samples, whereas KL-1 and CA-19-9 stained approx. 70% of all positive samples in each case. The occurrence of stained cells in the peritoneal cavity correlated with classical prognostic factors (TNM classification).

Immunocytochemical detection and phenotypic characterization of micrometastatic tumour cells in bone marrow of patients with prostate cancer

Monoclonal antibodies (mAbs) specific for cytokeratins are potent probes for the identification of disseminated individual epithelial tumour cells in mesenchymal organs such as bone marrow. We have used a monoclonal antibody (mAB) against cytokeratin 18 (CK18) for the detection of individual metastatic tumour cells in bone marrow aspirates from 84 patients with carcinoma of the prostate. CK18+ cells were detected in a sensitivity of 1 per 8 x 10(5) marrow cells using the alkaline phosphatase anti-alkaline phosphatase (APAAP) system for staining. We were able to detect CK18+ tumour cells in the marrow of 33% of patients with stage N0M0 prostate cancers. The incidence of CK18+ cells showed a significant correlation with established risk factors, such as local tumour extent, distant metastases and tumour differentiation. For further characterization of such cells in patients with prostate cancer, we developed an immunocytochemical procedure for simultaneous labelling of cytokeratin component no. 18 (CK18) and prostate-specific antigen (PSA). In a first step, cells were incubated with a murine mAb against PSA, followed by gold-conjugated goat anti-mouse antibodies. In a second step, a biotinylated mAb to CK18 was applied as primary antibody and subsequently incubated with complexes of streptavidin-conjugated alkaline phosphatase, which were developed with Newfuchsin substrate. The binding of gold-labelled antibodies was visualized by silver enhancement. CK18+ cells co-expressing PSA were found in bone marrow aspirates from 5 out of 14 patients with carcinomas of the prostate. The specificity of CK18 for epithelial tumour cells in bone marrow was supported by negative staining of 12 control aspirates from patients with benign prostatic hyperplasia (BPH).(ABSTRACT TRUNCATED AT 250 WORDS)

Detection and characterization of residual disease in breast cancer

Although micrometastatic tumor cell spread largely determines the prognosis of patients with operable breast cancer, it is usually missed by conventional tumor staging. Several groups (including ours) have therefore developed immunocytochemical and molecular assays that allow the specific detection and characterization of individual carcinoma cells disseminated to bone marrow, blood, and lymph nodes. These assays may improve the prognostic precision of the current classification systems and may provide a tool for the early assessment of the therapeutic effects of anticancer drugs on micrometastatic cells in individual patients. Another aspect of such methods is that they enable detection of tumor cell contamination in stem cell grafts and validation of the efficiency of purging techniques. The most extensive experience exists with immunocytochemical methods, some of which have the potential to serve as a benchmark for less validated molecular methods. Still, the specificity and sensitivity of immunocytochemical detection of single cancer cells are affected by several variables, which include the intricacies of antigen expression, the lack of distinct morphological characteristics, the size of the analyzed sample, and the staining techniques for visualization of antibody binding. This article provides a critical review of the opportunities and pitfalls related to new methods for the detection and monitoring of minimal residual disease in breast cancer.

Methodological analysis of immunocytochemical screening for disseminated epithelial tumor cells in bone marrow

The emerging clinical relevance of bone marrow micrometastasis has prompted several investigations, using a variety of immunocytochemical approaches. The present study was designed to evaluate some of the variables affecting the immunocytochemical detection of individual epithelial tumor cells in bone marrow. Using an alkaline phosphatase-antialkaline phosphatase staining technique, we evaluated bone marrow aspirates from 358 patients with primary carcinomas of the breast (n = 150), lung (n = 66), prostate (n = 42), or colorectum (n = 100). Individual tumor cells in cytological preparations were detected with monoclonal antibody (MAb) CK2 to the epithelial cytokeratin component 18 (CK18), which has been validated in extensive clinical studies. In addition, the utility of the broad-spectrum MAb A45-B/B3 was explored in this study. The high specificity of MAbs CK2 and A45-B/B3 was supported by analysis of bone marrow from 75 noncarcinoma control patients and by double-marker analysis with MAbs to mesenchymal marker proteins (CD45 and vimentin). In contrast, MAbs E29 and HMFG1, directed to mucin-like epithelial membrane proteins, cross-reacted with hematopoietic cells in 26.7-42.7% of all samples tested. The majority of the 154 positive samples (43.0%) from cancer patients displayed less than 10 CK18-positive cells per 8 x 10(5) marrow cells analyzed. The detection rate, however, was affected by blood contamination of the aspirate, the number of aspirates analyzed, and the number of marrow cells screened per aspiration site. Comparative immunostaining of bone marrow specimens with MAbs CK2 and A45-B/B3 indicated that downregulation of CK18 in micrometastatic carcinoma cells occurs in about 50% of the 172 samples analyzed, regardless of the primary tumor origin.(ABSTRACT TRUNCATED AT 250 WORDS)