The immunohistochemical assessment of occult regional lymph node metastases in patients with T3pN0M0 prostate cancer before definitive radiotherapy

Abstract

Objective To detect occult regional lymph node metastases in patients with T3pN0M0 prostate cancer not recognized by routine haematoxylin and eosin staining, and to evaluate the clinical relevance of this ®nding. Patients and methods Formalin-®xed and paraf®n-embedded pelvic lymph nodes (1118) from 92 patients were evaluated by immunohistochemistry using antibodies for prostate speci®c antigen (PSA) and pancytokeratin (AE1/AE3). Of the tumours, 14% were well, 69% moderately and 17% poorly differentiated. The extent of tumour was categorized as T3pN0M0 in all patients, who were referred for de®nitive radiotherapy after pelvic staging lymphadenectomy. The median (range) serum PSA value before treatment was 18.5 (0.4±342) mg/L. After radiotherapy, the patients were followed by assessing biochemical progression, pelvic recurrence and/or development of distant metastases. The median (range) observation time for all patients was 61 (16±136) months.Results Occult lymph node metastases were detected in four (4.4%) of the 92 patients. Patients with or without occult metastases had similar serum PSA levels and histological grades. None of the four patients with occult metastases progressed, compared with 37 of the 88 (42%) with no such metastases. Conclusion Using immunohistochemistry the detection rate of occult lymph node metastases in patients with T3pN0M0 prostate cancer is low. The occurrence of such metastases is probably unrelated to the serum PSA value before treatment. The short-term outcome of patients subsequently treated with de®nitive radiotherapy does not seem to be associated with the ®nding of occult lymph node metastases, but longterm follow-up is needed. So far, the results do not justify the search for occult lymph node metastases as a routine procedure in these patients

Tumor cells, rather than dendritic cells, deliver antigen to the lymph node for cross-presentation

“…First, lymph nodes that are considered by pathologists to be tumor negative (‘N0 disease’), 48 may actually have barely detectable numbers of tumor cells which are actually delivering antigen and cross priming tumor-specific T cells. Second, the localized TDLN CTL response may be controlling the spread of tumor cells to distal sites, that is, the presence of low-level metastasis to TDLNs may not per se be a negative indicator but would be the source of tumor-restricting CTL.…”

Clinical Value of Immunohistochemically Detected Lymphatic and Vascular Invasions in Clinically Staged Endometrioid Endometrial Cancer

“…12,13 Pancytokeratin epithelial cell marker immunostaining was accomplished using the streptavidin-biotin peroxidase method by mouse monoclonal anticytokeratin clone AE1/AE3 (0.165 Kg/mL; dilution, 1:50; Zymed Laboratories, San Francisco, Calif ), a Vectastatin avidin-biotin complex detection system (Vector Laboratories, Burlingame, Calif ), with color developed using 3,3diaminobenzidine tetrahydrocholoride. Endothelial cells on the same section were then immunostained with monoclonal mouse antiYhuman CD31 endothelial cell marker (0.45 Kg/mL; dilution, 1:50; Dako Corporation, Calif ), similarly detected with Vectastain avidin-biotin complex detection system, and the color was developed using a VIP substrate kit (Vector Laboratories).…”

Assessment of the depth of myometrial invasion in stage I endometrioid endometrial cancer using pancytokeratin immunohistochemistry

“…Four‐micron sections were cut from the representative blocks for immunohistochemical staining. These sections were immunostained in accordance with established techniques for pancytokeratin (PCK) ( 16,17 ) . Sections were first deparraffinized using xylene and were then rehydrated.…”