Nucleoli cytomorphology in cutaneous melanoma cells – a new prognostic approach to an old concept

Abstract

BackgroundThe nucleolus is an organelle that is an ultrastructural element of the cell nucleus observed in H&E staining as a roundish body stained with eosin due to its high protein content. Changes in the nucleoli cytomorphology were one of the first histopathological characteristics of malignant tumors. The aim of this study was to assess the relationship between the cytomorphological characteristics of nucleoli and detailed clinicopathological parameters of melanoma patients. Moreover, we analyzed the correlation between cytomorphological parameters of nucleoli and immunoreactivity of selected proteins responsible for, among others, regulation of epithelial-mesenchymal transition (SPARC, N-cadherin), cell adhesion and motility (ALCAM, ADAM-10), mitotic divisions (PLK1), cellular survival (FOXP1) and the functioning of Golgi apparatus (GOLPH3, GP73).MethodsThree characteristics of nucleoli – presence, size and number – of cancer cells were assessed in H&E-stained slides of 96 formalin-fixed paraffin-embedded primary cutaneous melanoma tissue specimens. The results were correlated with classical clinicopathological features and patient survival. Immunohistochemical analysis of the above mentioned proteins was described in details in previous studies.ResultsHigher prevalence and size of nucleoli were associated with thicker and mitogenic tumors. All three nucleolar characteristics were related to the presence of ulceration. Moreover, microsatellitosis was strongly correlated with the presence of macronucleoli and polynucleolization (presence of two or more nucleoli). Lack of immunologic response manifested as no TILs in primary tumor was associated with high prevalence of melanoma cells with distinct nucleoli. Interestingly, in nodular melanoma a higher percentage of melanoma cells with prominent nucleoli was observed. In Kaplan-Meier analysis, increased prevalence and amount, but not size of nucleoli, were connected with shorter cancer-specific and disease-free survival.Conclusion(1) High representation of cancer cells with distinct nucleoli, greater size and number of nucleoli per cell are characteristics of aggressive phenotype of melanoma; (2) higher prevalence and size of nucleoli are potential measures of cell kinetics that are strictly correlated with high mitotic rate; and (3) high prevalence of cancer cells with distinct nucleoli and presence of melanocytes with multiple nucleoli are features associated with unfavorable prognosis in patients with cutaneous melanoma.

Prognostic significance of nucleolar assessment in invasive breast cancer

“…A high nucleolar count showed significant associations with poor BCSS and shorter DMFS in both training and validation cohorts, and also OS in the external validation cohort. An association between prominent nucleoli and poor prognosis has also been reported in melanoma and prostatic cancer…”

“…However, there are currently no consensus histopathological guidelines with which to evaluate nucleoli in BC clinical practice. Previous studies assessing the prognostic significance of nucleoli in BC lacked objective criteria for scoring nucleoli, and did not identify optimal cut‐off points for prognostic stratification . In the current study, nucleoli were assessed with a variety of scoring methods in a large cohort of invasive BCs with long‐term follow‐up data, to determine the most reproducible assessment method while also providing prognostic value.…”

“…proto‐oncogene proteins). Prominent nucleoli constitute an indication of cellular kinetics and cytobiochemical changes that occur in cancer cells . In carcinoma, the association of nucleolar morphometric changes with poor patient prognosis is noteworthy, and there is increasing evidence from independent data that suggests an active role of the nucleolus in tumorigenesis …”

“…The main disadvantage of the modified Helpap method is the lack of information on the number of FVs or the number of cells with prominent nucleoli to be scored, or even the size of nucleoli to be considered. Although we followed the method recommended by Donizy et al . in melanoma, which used 20% of the tumour cells with prominent nucleoli, it was still more subjective than counting a defined number of FVs.…”

“…inconspicuous) or single less prominent nucleoli that were difficult to see at ×20 magnification were observed. A score of 3 was assigned if prominent nucleoli, which were easily seen at ×10 magnification and were identified in at least 20% of the tumour or dysmorphic/multiple nucleoli were present. A score of 2 was assigned to those tumours with nucleoli not scored 1 or 3.…”