Tissue microarray-based evaluation of Chromatin Assembly Factor-1 (CAF-1)/p60 as tumour prognostic marker.

In this study we aimed to confirm the emerging role of Chromatin Assembly Factor 1 (CAF-1 p60) as a new proliferation and prognostic marker for cancer and to test the usefulness of the tissue microarray technique (TMA) for CAF-1 p60 rapid screening in several human malignancies. CAF-1 is a histone chaperone, regulating chromatin dynamics during DNA replication and repair in eukaryotics. TMA is a powerful high-throughput methodology in the study of cancer, allowing simultaneous assessment of different biomarkers within large numbers of tissue specimens. We generated TMA taking 3 mm diameter-core biopsies from oral squamous cell carcinoma, prostate cancer, salivary gland tumours and skin melanoma specimens, which had been previously tested for CAF-1 p60 on routine tissue sections. We also analysed, for the first time, 30 larynx and 30 skin squamous cell carcinomas. CAF-1 p60 resulted over-expressed in both the tissue sections and the TMA specimens, with the highest levels of expression in tumours which were more aggressive and metastasizing. Notably, a high degree of agreement was found between the CAF-1 p60 assessment on TMAs and on routine tissue sections. Our findings confirm the prognostic role of CAF-1 p60 and indicate TMA as a really advantageous method for CAF-1 p60 immunohistochemical screening, allowing savings on both tissue quantity and operator-time.

Overexpression of Chromatin Assembly Factor-1/p60 helps to predict the prognosis of melanoma patients.

BACKGROUND: Cutaneous melanoma (CM) is the most lethal form of skin malignancy, which registers a constant increase in incidence worldwide. The identification of molecular alteration(s) involved in its biological aggressiveness represents a major challenge for researchers, considering that existing therapies are ineffective to treat metastasizing cases. The epigenetic control of chromatin dynamics during DNA synthesis, replication, and repair is fundamental for the orderly progression of cell proliferation. The Chromatin Assembly Factor 1 (CAF-1) complex acts as a major regulator of this process; its intermediate (p60) subunit has been recently proposed as a novel proliferation and prognostic marker for several tumors. We aimed to establish if the evaluation of the expression of CAF-1/p60 in primary CM may help define the prevision of outcome of patients. METHODS: Immunohistochemistry with anti-CAF-1/p60 was performed on paraffin-embedded tissue sections of 130 cases of primary CM retrieved from the archive files of the Department of Biomorphological and Functional Sciences, Section of Pathology, University "Federico II" of Naples, Italy. Results were compared with histopathological and follow-up data of patients. RESULTS: CAF-1/p60 was expressed in all CM. A significant statistical association between the overexpression of the protein and the occurrence of skin, node and/or distant metastases (P < 0.05) emerged, independently from histopathological prognostic factors. CONCLUSIONS: CAF-1/p60 looks promising as a new prognostic marker for CM and sheds new light on the molecular events associated with photocancerogenesis and melanoma biology.The screening for CAF-1/p60 might contribute to the molecular sub-classification of CM, with improved translational outcomes.

Overexpression of chromatin assembly factor-1/p60 predicts biological behaviour of laryngeal carcinomas.

This study analysed the immunohistochemical expression of the CAF-1/p60 protein in laryngeal cancers. CAF-1/p60 assumes an independent discriminative and prognostic value in laryngeal neoplasms; the presence of this protein in carcinoma in situ compared with laryngeal precancerous and larynx infiltrating tumours. We assessed the immunohistochemical expression of CAF-1/p60 in 30 cases of moderate and/or severe dysplasia, 30 cases of carcinoma in situ and 30 cases of laryngeal squamous cell carcinoma (LSCCs). CAF-1/p60 expression increased significantly according to the high index of neoplastic cellular replication; therefore, CAF-1/p60 was overexpressed in neoplastic cells and its moderate-severe expression is correlated with poorer prognosis compared to less expression. In conclusion, overexpression of the CAF-1/p60 protein is related to a risk of higher morbidity and mortality and is a reliable independent prognostic index of laryngeal carcinoma. CAF1-p60 protein overexpression can be used in cancer management as an indicator of malignant evolution, especially in carcinoma in situ.

The proliferation marker Chromatin Assembly Factor-1 is of clinical value in predicting the biological behaviour of salivary gland tumours.

Salivary gland tumours (SGT) constitute a diagnostically challenging group of neoplasms with frequently unpredictable clinical outcome. The proliferation rate facilitates the identification of aggressive SGT. The Chromatin Assembly Factor-1 (CAF-1) is a major epigenetic regulator of nuclear chromatin organization during DNA replication. It plays a critical function in human tumourigenesis and has been proposed as a new proliferation and prognostic marker for some malignancies. This study focused on the role of CAF-1/p60 protein as a marker of clinical value for SGT. The expression of CAF-1/p60 was evaluated by immunohistochemistry on a retrospective series of 362 surgically excised benign and malignant SGT with different histogenesis and, when available, on fine-needle pre-surgical cytological biopsies. The resulting data were compared with traditional prognostic parameters, including the expression of the routine proliferation marker ki67/MIB1. CAF-1/p60 was detectable in all SGT, with highest degree of expression in metastasizing malignant tumours. Moreover, the cases of benign tumours which progressed to carcinoma during the follow-up, showed significantly higher CAF-1/p60 expression than non-progressing benign SGT, both on histological sections and cytological smears of the primary tumour. Cox's multiple regression analysis selected CAF-1/p60 expression as the best independent predictor of cancer development for benign SGT (p<0.0001), and the best independent predictor of metastasis onset for malignant tumours (p<0.0004). Overexpression of CAF-1/p60, on histological and/or cytological samples, characterizes malignant SGT with aggressive behaviour, irrespective of their specific histotype, and allows the early diagnosis of progression toward malignancy of morphologically benign tumours.