Molecular staging of prostate cancer with the use of an enhanced reverse transcriptase-PCR assay

Prostate-specific antigen-producing cells in the bone marrow of a patient with early-stage prostate cancer

This report describes a clinical case that supports the hypothesis that occult bone marrow disease may exist even in early-stage and low prostate-specific antigen (less than 10 ng/mL) prostate cancer. The concept of adding androgen suppression to definitive local therapy in these patients is discussed.

Increased analytical sensitivity of RT-PCR of PSA mRNA decreases diagnostic specificity of detection of prostatic cells in blood

The diagnostic specificity of the detection of disseminated prostatic cells by reverse-transcriptase polymerase chain reaction (RT-PCR) of PSA mRNA was investigated. A sensitive nested PCR was developed. In blood samples from 10 healthy female and 10 healthy male persons examined by RT-PCR, mRNA of PSA was detected 3 times in each group. In the groups of patients suffering from benign prostate hyperplasia and prostate cancer, 6 of 11 and 5 of 12, respectively, gave positive RT-PCR results. With increasing analytical sensitivity of the RT-PCR of PSA mRNA, the diagnostic specificity of the assay is decreased. Further development of this diagnostic method requires the introduction of the quantitative PCR which may make possible discrimination between prostatic and non-prostatic source of PSA mRNA by quantification.

NASBA technology: isothermal RNA amplification in qualitative and quantitative diagnostics

Nucleic acid amplification technologies allow for the development of highly sensitive and specific diagnostic assays. The capacity to amplify and detect analyte targets, which may be present in a clinical sample as a single copy; is characteristic of many of these amplification technologies. NASBA is an isothermal method of nucleic acid amplification with such capability, and is particularly well suited for the amplification of RNA analytes. NASBA utilizes the coordinated activities of three enzymes (AMV-RT, RNase H, T7 RNA polymerase), and two oligonucleotide primers which are specific for the analyte target. The amplification process is part of a total system which includes a versatile nucleic acid isolation procedure, and powerful detection methodology. In this report, the development of NASBA technology for the detection of human Retrovirus RNA will be discussed. Specifically, a qualitative NASBA assay for the RNA of HTLV I, and a quantitative NASBA assay for HIV-1 will be described.

Can prostate-specific antigen reverse transcriptase-polymerase chain reaction be used as a prospective test to diagnose prostate cancer?

The present study addressed the question as to whether prostate-specific antigen reverse transcriptase-polymerase chain reaction (PSA RT-PCR) could be used to identify prospectively men who have prostate cancer and to help determine which patients with an initially negative biopsy would benefit from rebiopsy. PSA RT-PCR was performed prospectively on 90 patients who were to have a prostate biopsy because of an elevated PSA level, an abnormal digital rectal examination, or both. PSA RT-PCR was performed, and the sensitivity of the test was enhanced by hybridization of the PCR with a 32P-labeled PSA cDNA probe (exons 3-5). Of the 90 men, 36 (40%) had prostate cancer on biopsy. Of these 36 men, 5 (13.9%) had a positive PSA RT-PCR finding, whereas 31 (84.1%) tested negative. Of 54 men with negative biopsies, 8 (14.8%) had a positive PSA RT-PCR result. The sensitivity of PSA RT-PCR for the detection of biopsy-proven prostate cancer was 13.9% and the specificity was 85.2%. Only 3 of 12 (25%) patients with advanced disease had a positive test result. The sensitivity of PSA RT-PCR for the detection of biopsy-proven prostate adenocarcinoma in men suspected of having prostate cancer is poor. Indeed, men without biopsy-proven prostate cancer are just as likely to have a positive result in the PSA RT-PCR as are men with cancer. Whether these men with negative prostate biopsies and positive PSA RT-PCR findings may eventually develop prostate cancer remains to be determined. At this time, PSA RT-PCR for the prospective detection of prostate cancer should be considered investigational.

Detection of micrometastatic prostate cancer cells in the bone marrow of patients with prostate cancer

Thirty-five patients with prostate cancer were examined for micrometastases to the bone marrow using reverse transcription-polymerase chain reaction (RT-PCR) with primers specific for the prostate-specific antigen (PSA) gene. Of nine patients with bone metastases detectable by bone scan imaging, five patients had PSA mRNA expression in the bone marrow detectable by RT-PCR. Of 26 patients with negative bone scan findings, seven patients had PSA mRNA expression detectable in the bone marrow. RT-PCR could detect micrometastatic prostate cancer cells in the bone marrow that were not detectable by bone scan imaging. Of 16 patients with a serum PSA concentration of 25 ng ml(-1) or greater, only nine (56.3%) had bone metastases detected by bone scans. Of the remaining seven patients, five had micrometastases to the bone marrow detected by RT-PCR. Overall, 14 of 16 patients (87.5%) with a serum PSA concentration of 25 ng ml(-1) or greater had metastatic bone diseases including bone marrow micrometastases. Of 19 patients with a serum PSA concentration of less than 25 ng ml(-1), two (10.5%) had only micrometastatic disease detected by RT-PCR. A significant correlation was observed between the incidence of bone involvement and the serum PSA concentration. This study suggests that RT-PCR will potentially develop into a relevant tool to assess bone involvement including bone marrow micrometastases and establish a precise correlation between serum PSA concentration and metastatic bone disease in patients with prostate cancer.

Detection of circulating thyroid cells in peripheral blood

BACKGROUND

Detection of circulating malignant thyroid cells may provide a method to identify postoperative patients at risk for metastatic thyroid cancer.

METHODS

On the basis of tissue specificity of thyroglobulin gene expression and the sensitivity of the reverse transcriptase-polymerase chain reaction (RT-PCR) analysis, we performed RT-PCR using primers for thyroglobulin on blood samples from patients with thyroid disease to detect thyroglobulin RNA transcripts. Postoperative peripheral blood samples from 100 patients, including patients with known metastatic thyroid cancer (six papillary and three follicular), thyroid cancer and no evidence of current metastases (63 papillary, 10 follicular, and five patients with both papillary and follicular), benign thyroid disease (six nontoxic nodular goiters), and normal volunteers (seven).

RESULTS

Thyroglobulin transcripts were detected in nine of nine patients with metastatic thyroid cancer, seven of 78 patients with thyroid cancer and no current metastases (although of these seven patients, five had a history of metastatic disease that had been previously treated by surgery, one had a coexisting parathyroid cancer, and one had both papillary and follicular thyroid cancers), zero of six patients with benign thyroid disease, and zero of seven normal volunteers. Identity of amplicons was confirmed by restriction enzyme digestion and by cloning and sequencing of RT-PCR amplified thyroglobulin fragment (the latter in a limited number of cases).

CONCLUSIONS

These data indicate that RT-PCR can be used to detect thyroglobulin mRNA in peripheral blood. The presence of these transcripts correlates with the existence of extrathyroidal disease.

Constitutive expression of high levels of prostate-specific antigen in the absence of prostate carcinoma

OBJECTIVES

To identify distinguishing serologic features in patients with stable marked elevation in prostate-specific antigen (PSA) and multiple negative biopsies.

METHODS

The study population consisted of 7 patients with a stable PSA level of greater than 20 ng/mL (average 27.0), followed for at least 34 months (average 56), and with two or more negative prostatic biopsies including transition zone biopsies. The PSA density (PSAD), rate of change in PSA, reverse transcriptase/polymerase chain reaction (RT/PCR), and free/total PSA were obtained.

RESULTS

Rate of change in PSA level was stable (0.18 +/- 1.2 ng/mL/yr), suggesting that there was no occult cancer; PSAD was high (0.34 +/- 0.5 ng/mL/cc), indicating that prostate size was not the sole cause of the elevation. The RT/PCR was negative in 6 of 7 patients, further decreasing the likelihood of an occult malignancy. Free versus total PSA was not consistent, averaging 16.8%, but with a range of 6% to 34%.

CONCLUSIONS

Novel PSA tests were not found to be useful in this cohort of patients with multiple negative biopsies and PSA elevations greater than 20 ng/mL. Additional studies with larger sample size are required to confirm this finding.

The role of the reverse-transcriptase polymerase chain reaction assay for prostate-specific antigen in the selection of patients for radical prostatectomy

Prostate cells present in the peripheral circulation can be detected using an enhanced reverse-transcriptase polymerase chain reaction (RT-PCR) for prostate-specific antigen (PSA) assay. In one study, preoperative enhanced RT-PCR for PSA status was a significant predictor of surgical pathology and postoperative biomechanical recurrence. The use of RT-PCR may enhance the urologist's ability to stage potential candidates for radical prostatectomy, as the assay is a more sensitive and specific predictor of microscopic extracapsular extension than conventional staging modalities. This highly adaptable assay also may have roles in screening for recurrence and in staging other solid tumors.

New approaches to adjuvant therapy for patients with adverse histopathologic findings following radical prostatectomy

Some men affected with clinically localized prostate carcinoma suffer life-threatening recurrence, despite previous treatment with surgery or radiation therapy, underscoring the need for new, effective, systemic adjuvant treatment approaches. Recent molecular mechanism-based prostate cancer drug discovery efforts have identified several candidate targets for systemic prostate cancer adjuvant therapy; however, traditional cancer treatment development algorithms may not be appropriate for many of the new treatment strategies. To best exploit the clinical potential of these molecular treatment strategies, novel translational research strategies are required to support hypothesis-driven clinical research and development.

Immunochemical detection of 5 alpha-reductase in human serum

This study represents a continuing effort to find a new biomarker for the diagnosis and management of prostatic cancer. Polyclonal antibodies were prepared to a peptide (CAKP) representing amino acids 28 to 43 of the 5 alpha-reductase type 2 isozyme. Using immunoaffinity-purified antibodies, the sera of 62 patients were examined by Western blot following polyacrylamide gel electrophoresis. A positive band was detected in the sera of several patients at 42 kDa compatible with the purified native glycosylated 5 alpha-reductase type 2. These bands were nullified on coincubation of the antibody with the CAKP peptide. Analysis by high-performance liquid chromatography and amino acid sequencing by N-terminal Edman degradation of the immunoaffinity-purified antigen to the antipeptide antibodies of a patient with adenocarcinoma of the prostate suggests that the 5 alpha-reductase type 2 isozyme may be linked to an immunoglobulin. An identical immunoaffinity-purified antigen to the CAKP peptide was isolated from a section of prostatic tissue from a different patient showing benign prostatic hypertrophy with severe dysplasia. It is suggested that an immunological response to the 5 alpha-reductase type 2 isozyme was elicited in both instances.

Serum prostate-specific antigen elevation in the post-radical prostatectomy patient

The management of postprostatectomy serum prostate-specific antigen elevation is hampered by the inability to determine the location of the recurrence accurately and the lack of data demonstrating a survival advantage from any of the available therapies. Treatment must be individualized for each patient.

Reverse transcriptase-polymerase chain reaction for prostate-specific antigen may be a prognostic indicator in breast cancer

Among women with node-negative breast cancer and small tumours, it is important to identify those with tumours that will recur, so that they may receive adjuvant therapy, while sparing those with tumours that will not recur the hazards of adjuvant treatment. A reverse transcriptase-polymerase chain reaction (RT-PCR) for prostate-specific antigen (PSA) may be used to identify circulating metastatic cells in patients with prostate cancer. Approximately 30% of breast cancer cells also produce PSA. Therefore, we tested the PSA RT-PCR assay on blood specimens from women with breast cancer. We evaluated 78 women at Mount Sinai Medical Center with histologically confirmed breast cancer. Venous blood (5 cm3) from the women was collected in ethylene diaminetetraacetic acid (EDTA)-treated collection tubes and approximately 400 ng of RNA from each sample was subjected to an RT-PCR. We were able to detect the amplified PSA fragment in 18 of 78 women with breast cancer; 7 of the 18 women with the PSA fragment had localised, small, node-negative tumours, both oestrogen receptor (ER) positive and ER negative. We could not detect the amplified PSA fragment in 20 normal women and 22 normal men. We conclude that PSA RT-PCR may be a useful method for determining the presence of circulating metastatic cells in some women with node-negative breast cancer, and therefore the potential for these women to develop recurrent disease and thus benefit from adjuvant therapy.

Detection of minimal disease in patients with solid tumors

The detection and elimination of minimal systemic disease in patients with solid tumors is one of the main current topics in clinical oncology. The present review focuses, therefore, on new diagnostic approaches to identify minimal disease in peripheral blood, bone marrow, and lymph nodes of patients with epithelial cancer as the major type of solid tumors in Western industrialized countries. These approaches may be used to improve tumor staging and monitoring of adjuvant therapies, as well as to detect tumor cell contamination in autologous stem cell grafts. Most investigators have developed either immunocytochemical assays with monoclonal antibodies to a variety of epithelial-specific cytoskeleton and membrane antigens or molecular methods based on the extensive amplification of a specific (c)DNA sequence by the polymerase-chain reaction (PCR). In immunocytochemical assays, antibodies to cytokeratins can be regarded as the most specific and sensitive probes to detect isolated epithelial tumor cells in bone marrow and blood. Molecular methods are based on the detection of either mutations in oncogenes and tumor suppressor genes (e.g., ki-ras and p53 genes) or the mRNA expression of tissue-specific and tumor-associated genes. mRNA species targeted in these assays encode cytokeratins, prostate-specific antigen, prostate-specific membrane antigen, carcinoembryonic antigen, and polymorphic-epithelial mucin. To introduce the available methods into clinical practice, standardized protocols need to be developed and validated in multi-center studies.

Detection of circulating prostate-specific antigen-positive cells in patients with prostate cancer by flow cytometry and reverse transcription polymerase chain reaction

The presence of prostate-specific antigen (PSA)-positive cells has previously been demonstrated in the peripheral blood of prostate cancer patients by flow cytometry (FC), but the identity of these cells has not been established. In this study, the reverse transcriptase polymerase chain reaction (RT-PCR) was compared with analytical FC in an attempt to detect and characterise these cells. Peripheral blood was obtained from 12 patients with newly diagnosed and untreated prostate cancer and five controls. Nine of the 12 patients with prostate cancer (75%) had circulating PSA-positive cells as shown by FC. Only one of those patients (11.1%) was found to express PSA mRNA by RT-PCR. The absence of PSA mRNA in the majority of samples showing PSA-positive cells suggests that they do not represent haematogenous micrometastases. PSA-positive cells in the blood could represent monocytes that express PSA, either following binding/phagocytosis of free serum PSA or phagocytosis of tumour cells.

Polymerase chain reaction in the detection of micrometastases and circulating tumor cells

BACKGROUND

The sensitive detection of circulating tumor cells and micrometastases may have important therapeutic and prognostic implications.

METHODS

The molecular detection of occult tumor cells can be accomplished by amplifying tumor specific abnormalities present in the DNA or mRNA of malignant cells with the polymerase chain reaction (PCR). This approach has been used mainly for hemato-lymphoid malignancies. The other main PCR strategy for the detection of minimal residual disease (MRD) involves amplification of tissue-specific mRNA. This method was applied for the detection of occult disease in solid tumors.

RESULTS

PCR was shown to be superior to conventional techniques in detecting circulating tumor cells and micrometastases allowing the identification of 1 tumor cell diluted with 10(6)-10(7) normal cells. The central question of whether PCR positivity reliably predicts relapse remains unanswered for many tumor types. Serial analysis of a large number of samples is needed and currently undertaken in many institutions.

CONCLUSIONS

PCR is a highly sensitive method for the detection of circulating tumor cells and micrometastases in solid and hematopoietic malignancies. If PCR positivity is found to be a reliable tool, this will likely have a major impact on the treatment of many cancers. Patients could be selected for systemic therapy at an earlier stage when the metastatic tumor burden is low. PCR may improve the preoperative staging of patients with epithelial malignancies and therefore help avoid unnecessary radical procedures. Furthermore, this test may be useful in monitoring the effectiveness of adjuvant therapy, the intensity and duration of which is tailored to the individual patient. The impact of this PCR based approach on clinical oncology is likely to be profound.

Optimized microvessel density analysis improves prediction of cancer stage from prostate needle biopsies

OBJECTIVES

Clinical staging of prostate cancer is inaccurate, often with significant upstaging on final pathologic review. We previously demonstrated the ability to predict extraprostatic extension of cancer by use of the Gleason score and serum prostate-specific antigen (PSA) measurements. Herein we present an interim analysis of data from an ongoing multi-institutional study to determine the predictive power of an enhancement of microvessel density analysis in combination with Gleason score and serum PSA to predict extraprostatic extension.

METHODS

We evaluated a total of 186 randomly selected biopsy samples and matched totally embedded radical prostatectomy samples with preoperative PSA concentrations and patient demographics. Gleason score and optimized microvessel density (OMVD) were determined from the needle biopsy samples; pathologic stage was verified by independent review of the radical prostatectomy samples. An automated digital image analysis system measured microvessel morphology and calculated the OMVD in the biopsy samples (Biostage; Bard Diagnostic Sciences, Seattle, Wash).

RESULTS

Prediction of extraprostatic extension was increased significantly when OMVD analysis was added to Gleason score and serum PSA concentration (P = 0.003).

CONCLUSIONS

Optimized microvessel density analysis significantly increases the ability to predict extraprostatic extension of cancer preoperatively when combined with Gleason score and serum PSA concentration. This method appears to be a useful tool that can assist with treatment decisions in selected patients.

A comparative analysis of prostate-specific antigen gene sequence in benign and malignant prostate tissue

OBJECTIVES

Different molecular forms of prostate-specific antigen (PSA) appear to be expressed by benign prostatic hyperplasia (BPH) compared with prostate cancer. These differences are not well understood and may arise from aberrant RNA splicing, altered protein glycosylation, or variant PSA complexing to macroglobulins. To our knowledge, a direct comparison of PSA mRNA sequences in BPH versus prostate cancer to account for these differences has not been reported. The purpose of this study was to compare the complete PSA mRNA gene sequences in benign and malignant prostate tissue to determine whether altered PSA phenotypes are a result of gene mutations and to compare the published PSA sequences.

METHODS

Total RNA was extracted from 17 prostate specimens from 8 patients, including matched benign and malignant prostate tissue in 6 patients. The samples were subjected to reverse transcriptase-polymerase chain reaction (RT-PCR) of the PSA coding sequence and part of the 3' untranslated region. Directed DNA sequencing was performed on these fragments.

RESULTS

The benign and malignant prostate tissue cDNA sequence data of both strands were aligned and a computer analysis revealed 100% match with no evidence of mutation in prostate cancer compared to normal tissue. Sequence analysis did not reveal point mutations or aberrant splicing in any of the samples, including the matched malignant and nonmalignant tissues. Comparison with published sequences revealed infrequent and inconsistent sequence differences.

CONCLUSIONS

These findings suggest that the PSA gene expressed in malignant prostate tissue is the wild type. PSA structural alterations previously reported in the literature may occur through post-transitional mechanisms. A detailed understanding of the possible differences in the PSA gene sequence is essential as we develop newer techniques that utilize RT-PCR to perform molecular diagnosis and staging of prostate cancer.

Is there a role for induction androgen deprivation prior to radical prostatectomy?

The potential advantages of neoadjuvant androgen deprivation include decreased prostatic size, reduced vasculature, and reduced incidence of positive margins. The potential disadvantages are the side effects of hormonal medication, cost, tissue reaction, treatment "delay," and progression of androgen-independent clones. Many theories have been postulated to explain the observed reduction in the incidence of positive margins with neoadjuvant hormonal treatment. It is possible that the reduced prostate size and the frequently found periprostatic tissue reaction facilitate dissection, allowing better cancer clearance. It is possible, however, that the fibrosis may also increase the surgical difficulty, which critics argue may increase the risk of a positive margin. It is difficult to conceive of a research methodology that could resolve this issue. The occurrence of tumor cell death is likely a more significant explanation for the improved results. Whether tumor cells beyond the prostatic capsule are consistently affected to pathologically downstage the disease is unknown. The careful pathologic assessment in the randomized trials discussed previously suggests that pathologic downstaging is not as common as earlier reports have suggested. Difficulty in interpreting pathologic specimens after neoadjuvant treatment must be considered. At this point, neoadjuvant hormonal treatment prior to surgery would appear appropriate for those patients at high risk of having a positive surgical margin. Specifically, this includes clinical stage T2b, PSA elevation greater than 10 to 20 ng/mL, and a high Gleason score on the prostatic biopsy. Research to date suggests that neoadjuvant hormonal therapy prior to radical prostatectomy has a significant effect in reducing the incidence of positive surgical margins. The treatment is well tolerated with minimal side effects. Whether this will translate into improved disease-free survival remains to be determined. Fortunately, the randomized trials have been completed and follow-up data will be forthcoming.

Role of cytokines and growth factors in promoting the local recurrence of breast cancer

The pathogenesis of local recurrence in breast cancer is not well understood. Breast-conserving surgery is particularly prone to local recurrence as it leaves behind breast tissue that may harbour occult cancer, and lends itself to enhanced intraoperative shedding of cancer cells due to narrower resection margins and transection of lymphatic channels. A review of clinical breast cancer studies as well as experimental research strongly suggests that these persisting cancerous cells are unlikely to develop into clinically evident disease if their environment remains unstimulated. However, an inordinately high local recurrence rate occurs at the surgical scar, and such recurrence must be triggered by the release of growth factors and cytokines into the healing wound. These factors can stimulate any available cancer cells which express the proper growth factor receptors. Perioperative strategies to neutralize this tumour cell-growth factor interaction should maximize local control.

Implications of prostate micrometastases in pelvic lymph nodes: an archival tissue study

OBJECTIVES

In the United States, radical retropubic prostatectomy for adenocarcinoma usually includes a staging pelvic lymphadenectomy. If frozen section analysis of the lymph nodes fails to reveal any evidence of metastases, the prostate is removed. We have previously noted that as many as 56% of patients undergoing radical prostatectomy demonstrate rising serum prostate-specific antigen (PSA) levels by 4 years postoperatively. This report was designed to determine whether micrometastases undetectable by conventional pathologic methods: could have accounted for these biochemical failures.

METHODS

A retrospective analysis of formalin-fixed paraffin-embedded pelvic lymph node material was undertaken using a reverse transcription-polymerase chain reaction (RT-PCR)-based assay designed to amplify messenger RNA from PSA. All specimens were obtained from a group of 57 patients with prostate cancer who had undergone staging pelvic lymphadenectomy at the time of radical prostatectomy, and whose long-term follow-up was known.

RESULTS

Although all of these nodes appeared to be free of tumor by conventional pathologic methods, a RT-PCR assay was used to identify evidence of prostate metastases in 44% of evaluable samples. Of these, 14 of 16 went on to manifest rising serum PSA values by 5 years postoperatively.

CONCLUSIONS

These results suggest that molecular staging of pelvic lymph nodes prior to planned therapy for clinically organ-confined prostate cancer may better distinguish between patients with local disease and those for whom local therapy alone will not be curative. To our knowledge, this is the first large-scale retrospective gene expression study published.

Molecular detection of prostate epithelial cells from the surgical field and peripheral circulation during radical prostatectomy

PURPOSE

Prostate cancer progression despite organ confined pathological assessment has been reported in a variable number of men after radical retropubic prostatectomy. To study this phenomenon, we used the prostate specific antigen (PSA) reverse transcriptase-polymerase chain reaction assay.

MATERIALS AND METHODS

We prospectively assayed the peripheral venous blood before, during and after surgical manipulation as well as the intraoperative field blood for PSA reverse transcriptase-polymerase chain reaction-positive cells in 22 men undergoing radical retropubic prostatectomy.

RESULTS

PSA reverse transcriptase-polymerase chain reaction-positive cells were identified in 20 of the 22 operative field samples (91%) and 4 of 16 (25%) had evidence of intraoperative hematogenous dissemination (p = 0.046). No significant association was identified among Gleason score, pathological stage and the PSA reverse transcriptase-polymerase chain reaction result.

CONCLUSIONS

Our results suggest that tumor cell spillage and less frequently hematogenous dissemination may be associated with operative manipulation of the prostate during radical retropubic prostatectomy and may potentially represent mechanisms of failure after radical retropubic prostatectomy.

C-Ki-ras mutations in peripheral blood of pancreatic cancer patients: a marker for early tumor metastasis

PURPOSE

To determine the incidence of circulating minimal malignant clone (CMMC) (harboring c-Ki-ras-2 mutation) in peripheral blood (PB) samples of untreated pancreatic cancer using polymerase chain reaction (PCR) analysis of c-Ki-ras-2 oncogene.

METHODS AND MATERIALS

Experiments were carried out in fresh tumor, peritoneal washings (PW), and PB samples of untreated pancreatic adenocarcinoma patients (both resectable and unresectable). Samples were taken from 16 patients diagnosed with pancreatic adenocarcinoma for the PCR analysis of mutated c-Ki-ras oncogene. Five tumor samples, 15 PB samples, and 3 PW samples were analyzed for point mutation of the c-Ki-ras gene at codon 12.

RESULTS

Out of five tumor samples analyzed for c-Ki-ras mutation, four were positive at the 12th codon. Out of total 15 PB samples, nine were positive for the c-Ki-ras point mutation at the 12th codon. All the positive PB samples showed a base substitution from GGT to GAT in the second position of the 12th codon. Out of three PW samples, two showed mutation at the second position from GGT to GAT similar to their PB and tumor samples.

CONCLUSION

Our study indicated the presence of the tumor cells (CMMC) in PB of pancreatic adenocarcinoma that can be identified by PCR analysis of c-Ki-ras oncogene. Patients with presence of CMMC in PB and mutation in PW had aggressive tumors that responded poorly to treatment.

Haematogenous dissemination of prostatic epithelial cells during radical prostatectomy

Radical prostatectomy is one treatment for organ-confined prostatic adenocarcinoma. Dissemination of malignant prostatic cells after radical prostatectomy could be partly due to prostate manipulation during dissection. We confirmed by assay of prostate-specific membrane antigen by reverse-transcription nested PCR that prostate manipulation seeded prostatic epithelial cells in the general circulation in 12 of 14 consecutive patients operated on for organ-confined prostate adenocarcinoma. Our results suggest that surgeons should approach radical prostatectomy with care to avoid seeding from the prostate gland. Antiandrogen therapy might reduce the haematogenous spread of prostatic cells during radical prostatectomy.

Elevated 12-lipoxygenase mRNA expression correlates with advanced stage and poor differentiation of human prostate cancer

OBJECTIVES

Prostate cancer is the most frequently diagnosed cancer and the second leading cause of cancer death in males in the United States. The mortality is due mainly to distant metastasis. Therefore, predicting the prognosis of prostate cancer patients is an important clinical problem. Previously, we demonstrated that a 12-lipoxygenase (12-LOX) metabolite of arachidonic acid, 12(S)-hydroxyeicosatetraenoic acid, enhances the invasiveness of prostate cancer cells and that a 12-LOX-selective inhibitor [N-benzyl-N-hydroxy-5-phenylpentanamide] reduces experimental metastasis in animal model systems. In this study, we investigated the potential of 12-LOX as a predictor for the aggressiveness of prostate cancer.

METHODS

The mRNA expression level of 12-LOX in 122 matching prostate normal and cancerous tissues were measured by quantitative reverse transcription- polymerase chain reaction. Possible association between 12-LOX expression and histologic grade, pathologic and clinical stage, margin positivity, age, and race was analyzed.

RESULTS

12-LOX mRNA levels were elevated in cancer cells and the expression associated with poor differentiation and invasiveness of prostate cancer. Overall, 46 (38%) of 122 evaluable patients showed elevated levels of 12-LOX mRNA in prostate cancer tissues compared with the matching normal tissues. A statistically significantly greater number of cases were found to have an elevated level of 12-LOX among T3, high grade, and surgical margin-positive than T2, intermediate, and low grade, and surgical margin-negative prostatic adenocarcinomas.

CONCLUSIONS

Our data suggest that elevation of 12-LOX mRNA expression occurs more frequently in advanced stage, high-grade prostate cancer and that 12-LOX may serve as an indicator for progression and prognosis of prostate cancer. This enzyme also may be a novel target for the development of anti-invasive and antimetastatic agents.

The role of transrectal ultrasound-guided biopsy-based staging, preoperative serum prostate-specific antigen, and biopsy Gleason score in prediction of final pathologic diagnosis in prostate cancer

OBJECTIVES

To evaluate the role of ultra sound-guided systematic and lesion-directed biopsies, biopsy gleason score, preoperative serum prostate-specific antigen (PSA) as three objective and reproducible variables to provide a reliable combination in preoperative identification of risk of extraprostatic extension in patients with clinically localized prostate cancer.

METHODS

The case records of 813 patients who underwent radical prostatectomy for clinically localized prostate cancer were analyzed. All had multiple systematic biopsies, two to three from each lobe, in addition to lesion-directed biopsies. Additionally, biopsies were done on seminal vesicles (SVs), if abnormal. Based on biopsy results, patients were classified as having stage B1 (T2a-T2b) or B2 (T2c) disease, depending on whether biopsies from one or both lobes were positive and stage C (T3) if there was evidence of SV involvement by biopsy of biopsies from areas of extracapsular extension as seen on transrectal ultrasound (TRUS) were positive. Logistic regression analyses with log likelihood chi-square test was used to define the correlation between individual as well as combination of preoperative variables and pathologic stage.

RESULTS

On final pathologic examination, 473 (58%) patients had organ-confined disease, 188 (23%) had extracapsular extension (ECE), with or without positive surgical margins, and 72 (9%) had SV involvement. Eighty (10%) patients had pelvic lymph node metastases. Biopsy-based staging was superior to clinical staging in predicting final pathologic diagnosis. Logistic regression analyses revealed that the combination of biopsy-based stage, preoperative serum PSA, and biopsy Gleason score provided the best prediction of final pathologic stage. Probability plots constructed with these data can provide significant information on risk of extraprostatic extension in individual patients.

CONCLUSIONS

This study demonstrates that TRUS-guided systematic biopsy in combination with preoperative serum PSA and biopsy Gleason score may provide a cost-effective approach for management decisions and prognostication in patients with prostate cancer.

Molecular forms of prostate-specific antigen and the human kallikrein gene family: a new era

Without question, much has been learned about the glycoprotein PSA in recent years. By increasing our understanding of this tumor marker's biochemical and physiologic properties, we will be able to improve its clinical utility. The discovery of the various molecular forms of PSA represents a significant advancement. Knowing the concentration and ratio of these PSA forms will be valuable in deciding which patients require further evaluation with transrectal ultrasound and prostate biopsy and which men can be monitored safely without undergoing further invasive testing. This information will be most valuable in treating the patient with a mildly elevated serum PSA level. Although assays are not yet available to detect specifically hK2, the striking similarities of hK2 to PSA, including selective expression in the prostate, suggest that this marker may also prove useful in prostate cancer management. Indeed, a new era of PSA testing has been entered, and the entire field of prostate cancer will benefit.