Raised prostate-specific antigen in adenocarcinoma of the colon

Diagnostic Value of Combinatorial Markers in Colorectal Carcinoma

Objectives: Blood-based tests have been shown to be an effective strategy for colorectal cancer (CRC) detection in screening programs. This study was aimed to test the performance of 20 blood markers including tumor antigens, inflammatory markers, and apolipoproteins as well as their combinations.

Methods: In total 203 healthy volunteers and 102 patients with CRC were enrolled into the study. Differences between healthy and cancer subjects were evaluated using Wilcoxon rank-sum test. Several multivariate classification algorithms were employed using information about different combinations of biomarkers altered in CRC patients as well as age and gender of the subjects; random sub-sampling cross-validation was done to overcome overfitting problem. Diagnostic performance of single biomarkers and multivariate classification models was evaluated by receiver operating characteristic (ROC) analysis.

Results: Of 20 biomarkers, 16 were significantly different between the groups (p-value ≤ 0.001); ApoA1, ApoA2 and ApoA4 levels were decreased, whereas levels of tumor antigens (e.g. carcinoembriogenic antigen) and inflammatory markers (e.g., C-reactive protein) were increased in CRC patients vs. healthy subjects. Combinatorial markers including information about all 16 significant analytes, age and gender of patients, demonstrated better performance over single biomarkers with average accuracy on test datasets ≥95% and area under ROC curve (AUROC) ≥98%.

Conclusions: Combinatorial approach was shown to be a valid strategy to improve performance of blood-based CRC diagnostics. Further evaluation of the proposed models in screening programs will be performed to gain a better understanding of their diagnostic value.

Reconnoitring the status of prostate specific antigen and its role in women

Prostate specific antigen is considered to be a tumour marker having maximum utility and specificity for prostate cancer since decades. After the discovery of methods to quantify different molecular fractions of prostate specific antigen (PSA), its usefulness in diagnosing early prostate cancer cases has increased tremendously. The "specificity" of PSA, is now challenged by many studies which proved that PSA, once believed to be secreted exclusively by prostatic epithelium, is also present in females. The exact biological role of extraprostatic PSA is still debatable though many theories substantiated by in vitro evidence has been put forward. With the advent of ultrasensitive analytical techniques, PSA is now quantifiable in female serum in its various molecular forms and this has led to many assumptions of it being useful as a marker in female breast cancers. In a similar scenario to prostate cancer, the ratio of free to total PSA is shown to be useful in detecting early breast cancer cases. It is also shown to be a good prognostic indicator and a predictor of response to therapy and recurrence. Apart from its role in breast cancer, it has been advocated to be a marker of hyper androgenic states in women like hirsutism and polycystic ovarian syndrome. Conflicting reports regarding the role of extra prostatic PSA is accumulating but it has been proven beyond doubt that PSA is no longer specific and confined to prostate gland. Various studies have registered that PSA is an ubiquitous molecule, secreted by hormone responsive organs and its synthesis is stimulated by androgens and progesterone but not oestrogens. In this article, a review of various literatures is done about the presence of extra prostatic PSA, its probable role in those sites as well as its utility as a tumour marker in breast cancer.

Prostate-specific antigen in the serum of women with benign breast disease

OBJECTIVES

Fibrocystic mastopathy is the most common benign breast disease. Available evidence suggests that the presence of breast cysts increases the risk of breast cancer. The purpose of the study was to evaluate and compare the detection rate of total and free prostate-specific antigen (PSA) in the serum samples of healthy women and in those of women with cystic mastopathy. Moreover, we compared PSA concentrations in the serum samples of the study groups.

STUDY DESIGN

The study population included 114 women with fibrocystic breast disease, with cysts measuring <10mm (Group I) and 62 with macrocysts measuring >10 mm (Group II). Forty-six healthy volunteers were enrolled in the study as a control group. We analyzed the frequency of the detection level and the mean serum concentrations of total and free PSA in women with mastopathy and in healthy participants. Total PSA (PSA-T) and free PSA (PSA-Free) were measured by an ultrasensitive fluoroimmunometric DELFIA assay (Prostatus PSA Free/Total Wallac, Turku, Finland). The detection limits was 0.01 ng/ml.

RESULTS

Our results showed the statistical significance of the fact that the detection rate of free and total PSA was higher in all women with mastopathy (Group I with II) than it was in the control group. There were no differences between Group I and Group II regarding the detection rate of the two forms of antigen and between the control group and Group II in the detection rate of total PSA. We also demonstrated that the mean concentration levels of both free and total PSA were significantly higher in the serum of women with mastopathy than in the control group.

CONCLUSION

These findings suggest that women with mastopathy, regardless of the size of the cysts, produce and release more PSA into the serum than women without breast pathology. The PSA may be a new marker for the assessment of benign breast disease.

Measurement of serum total and free prostate-specific antigen in women with colorectal carcinoma

We investigated the diagnostic value and the relationship with clinicopathological features of total and free prostate-specific antigen by measuring the concentrations of these markers in the sera of 75 women with colorectal carcinoma and in 30 healthy women. Measurements were performed by immunoradiometric assay which utilizes monoclonal and polyclonal anti-prostate-specific antigen antibodies; the lowest detection level for both markers was 0.01 ng ml(-1). Free prostate-specific antigen levels were significantly higher in women with colorectal carcinoma than healthy women (P=0.006). The percentage of free prostate-specific antigen predominant (free prostate-specific antigen/total prostate-specific antigen >50%) subjects was 20% in colorectal carcinoma patients and 3.3% in healthy women (P=0.035). Cut-off values were 0.34 ng ml(-1) for total prostate-specific antigen and 0.01 ng ml(-1) for free prostate-specific antigen. In women with colorectal carcinoma, total prostate-specific antigen positivity was 20% and free prostate-specific antigen positivity was 34.6%. When compared to negatives, total prostate-specific antigen positive patients had a lower percentage of well-differentiated (P=0.056) and early stage (stages I and II) tumours (P=0.070). However, patients with predominant free prostate-specific antigen, had a higher percentage of well-differentiated (P=0.014) and early stage tumours (P=0.090) than patients with predominant bound prostate-specific antigen. In conclusion, although the sensitivity of free prostate-specific antigen predominancy is low (20%), in distinguishing women with colorectal carcinoma than healthy women, its specificity is high (96.7%). Free prostate-specific antigen predominancy tends to be present in less aggressive tumours. These findings may indicate clinical significance of preoperative measurement of serum total and free prostate-specific antigen in women with colorectal carcinoma.