All-trans retinoic acid and 1 alpha,25-dihydroxyvitamin D3 co-operate to promote differentiation of the human promyeloid leukemia cell line HL60 to monocytes.

A basis for differentiation therapy of leukemias is provided by knowledge of agents which induce specific lineage maturation. All-trans retinoic acid (RA) induces differentiation of HL60 cells to neutrophils and is used to treat acute promyelocytic leukemia. We observed that RA did not induced neutrophil differentiation in serum-free grown HL60 cells whereas 50 nM 1 alpha,25-dihydroxyvitamin D3 (D3) induced maximal monocyte differentiation. Increasing RA concentrations reduced the D3 concentration required for monocyte differentiation. Cells treated with 5 nM D3 showed little response, but differentiated maximally with 5 nM D3 and 10 nM RA. The D3 analogs MC903, EB1089 and KH1060 were more potent inducers of monocyte differentiation. The extent to which analog activity was increased after cotreatment with RA was inversely related to potency. Twenty-four hour treatment with 10 nM RA primed cells for response to 5 nM D3; the reverse sequence being ineffective. Priming with 10 nM RA, or subsequent treatment with D3 (5 nM), did not alter expression of mRNAs encoding receptors for D3 (VDR), RA (RAR alpha) or 9-CIS RA (RXR alpha, beta, gamma). That RA promotes both neutrophil and monocyte differentiation has implications for the use of RA and D3 in treatment of leukemias and provides insight into mechanisms whereby RAR, VDR and RXR facilitate monocyte differentiation.

Down-regulation but not phosphorylation of stathmin is associated with induction of HL60 cell growth arrest and differentiation by physiological agents.

Stathmin is a cytosolic phosphoprotein that has an important but, as yet, undefined role in cell proliferation and differentiation. Induction of growth arrest and differentiation of HL60 cells to monocytes by phorbol 12-myristate 13-acetate is associated with rapid phosphorylation of the protein. Stathmin phosphorylation was not seen when HL60 cells were induced to differentiate to monocytes, by 1 alpha, 25-dihydroxyvitamin D3, and to neutrophils, by all-trans retinoic acid and granulocyte colony stimulating factor. In all the above instances, stathmin expression was down-regulated. Thus, increased stathmin phosphorylation is not required for cell growth arrest or differentiation or down-regulation of stathmin expression.

Nucleolar organising regions in cervical intraepithelial neoplasia.

The variations in the numbers of nucleolar organising regions (NORs) among different grades of cervical intraepithelial neoplasia (CIN) were investigated using a silver staining technique. Twenty four biopsy specimens were studied (six normal and six of each of the three grades of CIN) by staining paraffin wax sections using a silver (AgNOR) method that stains the NORS as multiple black dots within nuclei (AgNORs). The number of AgNORs in the nuclei of cells in the basal half of the squamous epithelium was counted, and the average number of AgNORs in each cell calculated for each specimen (the AgNOR count). There was no difference in the number of AgNORs in the squamous epithelium of normal biopsy specimens and those showing CIN1 and CIN2, but there was a small but significant increase in the CIN3 group.

AgNOR counts and determination of malignancy in stromal tumours of the stomach and small intestine.

Twenty four primary stromal tumours of the stomach and small intestine were investigated by silver staining of interphase nucleolar organiser regions (AgNORs) in an attempt to obtain an objective criterion for prediction of malignant tumour behaviour. Malignant tumours tended to have higher AgNOR counts than their benign counterparts, but this increase was small and there was some overlap between the two groups. There was a correlation between the mean AgNOR count and the mitotic count. There was no correlation between tumour size and these two measurements. This study suggests that in these stromal tumours the AgNOR count is not a useful independent predictor of malignant behaviour.

Detection of Ki67 antigen by a new sheep polyclonal antiserum.

This report describes the characterisation of a polyclonal sheep antiserum against the Ki67 antigen. On western blots, this antiserum recognises a pair of bands of high molecular weight identical with those seen with another polyclonal Ki67 antiserum and the MIB 1 monoclonal antibody. The new antiserum showed nuclear staining of a proportion of cells in paraffin wax embedded tissue sections following antigen retrieval using a microwave oven or pressure cooker. This staining pattern was blocked by incubating the serum with the peptide used as immunogen. The proportion and distribution of immunostained nuclei was identical with that seen with the alternative reagents that recognise the Ki67 antigen. The new reagent stained the same proportion of cells when used over a wide range of dilutions. There was no cross-reactivity with unrelated antigens sometimes detected by the monoclonal antibodies.

Immunohistochemical demonstration of CD23 expression on lymphocytes in rheumatoid synovitis.

The leucocyte antigen CD23 is expressed by B lymphocytes following activation by a number of stimuli and functions as an IgE receptor, and in its soluble form, as a putative B cell growth factor. The expression of CD23 on the surface of lymphocytes in paraffin wax sections of synovial biopsy specimens was studied using a novel mouse monoclonal antibody, BU38. Specimens were investigated from nine cases of rheumatoid arthritis, six cases of osteoarthritis, and eight cases of chronic inflammation in articular and non-articular tissues. CD23 was expressed on a high proportion of lymphocytes in all forms of chronic inflammation and was not specific for rheumatoid arthritis. It may be a characteristic feature of any chronic inflammatory response. As CD23 was found on the surface of lymphocytes in many cases of these arthritides, sCD23 in serum or synovial fluid may yet prove a useful marker for the severity of the inflammatory infiltrate.

Expression of proliferating cell nuclear antigen (PCNA) in gastric carcinoma: no evidence for prognostic value.

It has been proposed that immunostaining with PC10, a monoclonal antibody against proliferating cell nuclear antigen (PCNA), is of prognostic value in gastric carcinoma. Gastric carcinomas from a series of 90 patients in whom survival data were known have been studied. There was no relation between the degree of PC10 immunostaining assessed semiquantitatively and survival.

Rapid peroperative assessment of axillary lymph node status using imprint cytology.

Sentinel lymph node biopsy for invasive breast cancer is a new technique that has been shown to be accurate in staging the axilla. Patients with a positive sentinel node will potentially need a second operation to clear the axilla. A reliable technique for assessing lymph nodes intraoperatively could potentially avoid this second procedure. This study aimed to assess the accuracy of peroperative imprint cytology of axillary lymph nodes in patients with invasive breast carcinoma. A total of 157 nodes were studied. One-hundred and nineteen nodes were both negative on imprint cytology and paraffin section. Thirty-eight nodes were positive on imprint cytology. Of these, 37 were positive on histology. Imprint cytology is a rapid technique that is inexpensive and has been shown to be reliable in this and other studies. It may prove to be of value in patients undergoing sentinel lymph-node biopsy for breast carcinoma.

The diagnosis of invasive lobular breast carcinoma. Does MRI have a role?

Invasive lobular breast carcinoma accounts for approximately 15% of all breast cancers and is difficult to detect using conventional breast imaging techniques. We report a comparison between clinical, ultrasound scan (USS), mammographic and magnetic resonance imaging (MRI) of 22 patients with invasive lobular breast carcinomas. Actual tumour size was ascertained by histopathology. MRI detected 21 of the 22 invasive lobular cancers whilst mammography and USS detected 16 and 20 respectively. 19 tumours were clinically palpable. MRI was more accurate at assessing tumour size than USS and clinical examination, both of which underestimated tumour size.

Redefining surgery for gastric cancer.

BACKGROUND: Despite encouraging retrospective and non-randomized trials, two large prospective, randomized trials of D1 vs D2 resections show double the mortality in the D2 group, with no increase in long-term survival. However, the D2 resection still offers the only hope of cure when N2 nodes are involved. We propose a reclassification of the International Union Against Cancer TNM "N" staging to a system with an anatomical basis that is useful in defining the surgery performed. Junctional nodes lying between the N1 and N2 tiers will act as a guide to surgery. Where these nodes are uninvolved, the probability of gastric bed (N2) involvement is low and the radical D2 dissection with its higher mortality and morbidity can be avoided.CONCLUSION: Such "stage-appropriate" surgery will reduce the number of D2 resections while ensuring that patients with N2 disease are not denied curative surgery. A prospective, randomized, controlled trial of targeted surgery is required.

Spontaneous regression of metastatic malignant melanoma of the parotid gland and neck lymph nodes: a case report and a review of the literature.

We report the case history of a patient with complete spontaneous regression of metastatic cutaneous melanoma with parotid and neck lymph node metastases. Complete spontaneous regression of metastatic melanoma is very rare, with an estimated incidence of 0.22%-0.27%. We review the literature on this subject. Elucidation of the process of spontaneous regression may offer the possibility of improved methods of treating and preventing cancer.

Schwannoma (neurilemmoma) of the tonsil.

Schwannoma of the tonsil is an extremely uncommon clinical entity with only one reported case in an adult in the medical literature to date. We report, to our knowledge, the first known case in a child.

The effect of different fixatives and length of fixation time on subsequent AgNOR staining for frozen and paraffin-embedded tissue sections.

The AgNOR technique has been used extensively in studies investigating the possibility that the numbers and appearances of the intranuclear structures stained are markers of malignancy. The method has the advantage of being applicable to many different types of histological material, including paraffin-embedded tissue. However, it has been suggested that the visualization of AgNORs is dependent on the type and time of fixation employed. This study set out to measure this effect with the following commonly-used fixatives: acetone, absolute ethanol, methanol, Carnoy's fluid, Bouin's fluid, 4% glutaraldehyde, 10% neutral buffered formalin and 10% formol-saline. Both frozen sections and blocks of fresh tonsil were fixed for varying times, the blocks of tissue then being processed routinely. With the frozen sections AgNORs were easier to discern than in sections of paraffin-embedded tissue, and more intranucleolar AgNORs were visible when alcoholic fixatives were used than with aldehyde fixation. The effects of different fixatives on AgNOR appearance in paraffin sections is, however, more complex. Despite the variation caused by different fixatives, AgNORs could be demonstrated adequately with all the fixatives studied. It is concluded that fixation is not a limitation to the study of AgNORs provided that the time and type of fixative is controlled.

Immunohistochemical evidence for the expression of proliferating cell nuclear antigen (PCNA) by non-proliferating hepatocytes adjacent to metastatic tumours and in inflammatory conditions.

The possibility that proliferating cell nuclear antigen (PCNA) is expressed by non-proliferating liver cells was investigated. Liver biopsies from 107 patients were investigated, which included histologically normal liver, metastatic tumour, and inflammatory lesions. PCNA was detected using immunohistochemical staining with the monoclonal antibody PC10. This was compared with the proportion of proliferating cells as assessed by immunostaining for the Ki-67 antigen using the monoclonal antibody MIB 1. Most cases of histologically normal liver showed few PC10-positive cells. PCNA-positive hepatocytes far outnumbered those positive with MIB 1 in specimens showing metastatic tumour or an inflammatory cell infiltrate. There was no relation between the degree of PCNA overexpression and the type of tumour present or the nature of the inflammatory lesion. Other cell types, including the biliary epithelium, did not show this large difference between the proportions of PC10- and MIB 1-positive cells. It is concluded that non-proliferating hepatocytes increase their levels of PCNA in a wide variety of pathological conditions. This may be mediated by cytokines released by tumour cells or inflammatory cells.

Silver staining of nucleolar organizer region associated proteins using polyethylene glycol as the protective colloidal developer.

A simple modification to the silver staining technique for the demonstration of nucleolar organizer region associated proteins is described. Polyethylene glycol 20,000 is used instead of gelatin as the colloidal developer. This modified technique remains a one stage procedure that is quick and easy to perform. It results in reduced precipitate and less non-specific staining with specimens in which it had been previously difficult to demonstrate these intranuclear silver staining structures.

Immunohistochemical determination of CD23 expression in Hodgkin's disease using paraffin sections.

The leukocyte antigen CD23 is expressed during B-cell development, and functions as an IgE receptor and a lymphocyte growth factor. We studied the expression of CD23 in paraffin sections of lymphoid tissue using the monoclonal antibody BU38. Fifteen cases of Hodgkin's disease, ten reactive lymph nodes, eight B-cell, and seven T-cell non-Hodgkin's lymphomas were analysed immunohistologically. CD23 positivity was seen on follicular dendritic cells and a small number of lymphocytes in reactive nodes. Thirteen of the 15 cases of Hodgkin's disease showed CD23 expression in both neoplastic cells and reactive lymphocytic infiltrate. The antigen was demonstrated in four of the B-cell and one of the T-cell tumours. CD23 may be important in mediating the mixed cellular infiltrate characteristic of Hodgkin's lymphoma.

Detection of the multidrug resistance marker P-glycoprotein by immunohistochemistry in malignant lung tumours.

BACKGROUND: The multidrug resistance marker P-glycoprotein (P-gp) was studied immunohistochemically in 78 primary malignant lung tumours. P-gp is a 170 kD transmembrane ATP dependent drug efflux pump which has been shown to be important in the resistance of some tumours to chemotherapy. Certain normal tissues express P-gp and tumours derived from these tissues are often insensitive to cytotoxic agents, showing raised P-gp levels innately or following chemotherapy or radiotherapy. METHODS: Samples from 78 patients undergoing surgery for primary malignant lung tumours were snap frozen and stained immunohistochemically using the monoclonal antibody C219 which reacts with a P-gp epitope. None of the study group had received chemotherapy or radiotherapy before surgery was performed. RESULTS: Twenty seven of the 78 lung tumours (34.6%) showed immunohistochemically detectable levels of P-gp which varied with tumour type; 17 of 54 squamous cell carcinomas (31.5%), seven of 15 adenocarcinomas (46.7%), and neither of two small cell carcinomas showing positive staining. In six of seven cases normal respiratory epithelium present showed the presence of P-gp. CONCLUSIONS: P-gp is immunohistochemically detectable in frozen tissue from a proportion of malignant lung tumours before exposure to radiotherapy or drugs associated with multidrug resistance. It may have a role in tumour resistance to cytotoxic drugs, but further clinical studies will be required to evaluate any correlation between P-gp levels and response to treatment.