Our data indicate disparities between the GlpeTH and the MqueTH patients regarding CRC cartography. To our knowledge, no other study has investigated and compared the clinicopathological features and the p53 pattern of expression of CRC in these populations.
There were no differences in age (p = 0.94), sex (p = 0.47), histology (p = 0.073) and tumour sites (p = 0.65) between CRCs in the GlpeTH and the MqueTH patients, although the percentage of men was slightly higher in the former patients (51.8%) than in the latter patients (46.6%) and, inversely the percentage of women was slightly lower (48.2% vs 53.4%). Approximately equivalent percentages of proximal colon (36.5%) and distal colon cancers (47.4%) were diagnosed in the MqueTH patients as compared with the high proportion of distal colon cancers diagnosed in the GlpeTH patients (54.2%). In accordance with this latter result, Dieye et al.  report that, among the 138 Guadeloupian patients recruited in 2008 (cancer registry data), 58.9% were males and 41.1% females, and that distal colon cancers were more frequent. Also, the data of Dieye et al. [11, 14] and Ngasseu et al.  confirm our results obtained with the MqueTH patients.
Our non-standardized results were also compared with those obtained for patients in Metropolitan France [11, 17, 18] and for Caucasian patients [1, 2, 4]. The proportion of colon cancer cases occurring before the age of 50 was found to be higher in the French departments (15% vs 2-6%), whereas the proportion of rectal cancer was found to be lower (12–16.1% vs 23-27%). Furthermore, compared with the Caucasian patients, African Americans are typically diagnosed with CRC at a younger age, with a higher incidence of tumours located on the proximal colon and with well-differentiated CRC [19–23]. Tanzanian patients (African) are diagnosed at a young age as well, however, moderately differentiated and rectosigmoid tumours in those patients were mostly represented .
Histopathological data was further discussed. Significant differences were found between the MqueTH and the GlpeTH patients regarding tumour grade (p < 0.0001), considered as an independent prognostic factor , tumour stage (p = 0.045) and depth of tumour invasion (p < 0.0001). Moderately (53.2%) and poorly differentiated CRCs (5.3%) were diagnosed in the GlpeTH patients, whereas CRCs were at early pTNM stages (66.2%). By contrast, well differentiated CRCs (84.7%) were more frequently diagnosed in the MqueTH patients, whereas pTNM stage IV CRCs were highly represented (10.2%). As a reminder, the value obtained for African American and Caucasian patients was 14% and for Metropolitan France patients it was 13-22% [17–22].
As far as p53, the “guardian of the genome”, is concerned , reviews of the literature indicate that its clinical significance in CRC is still raising a controversial debate, probably due to the mode of patient selection, the origin of patients, tumour sites or the use of different p53 antibodies for IHC [6, 26–32]. For example, the study of Iacopetta  indicates that a high frequency of p53 mutation was observed in distal colon and rectal cancer; however, these alterations in the p53 gene are likely to have very little or no prognostic significance in CRC patients treated with surgery alone. This could be the case for the GlpeTH and the MqueTH patients included in the present study. On the other hand, the study of Mane et al.  indicates that approximately equivalent proportions of distal and proximal colon cancers were positive for p53 in African American patients, whereas distal colon cancer from white patients were more frequently positive for p53 than proximal colon cancer was. The authors conclude that nuclear p53 was a valuable indicator of poor prognosis only for white patients with tumours located on the proximal colon. Diez et al.  show that p53 overexpression was more frequent in distal than in proximal tumours, and the authors concluded that p53 exhibited different prognostic values in distal and proximal colon. Nevertheless, when we used the monoclonal DO-1 p53 antibody to visualize the p53 expression and location, our IHC analyses indicated that p53 overexpression was observed in 57.9% and 65.8% of the CRCs of the GlpeTH and the MqueTH patients, respectively, which is in accordance with the 40-81% range of p53 positivity observed in previous reports [9, 10, 27–32]. Staining was restricted to the nuclei of malignant cells. Regarding the GlpeTH patients, 61.4% of the distal colon cancers were p53 positive, versus 31.8% of the proximal colon cancers. Regarding the MqueTH patients, equivalent proportions of the distal and the proximal colon cancers were positive for p53. The paradox noticed for the clinical, pathological data was also found for the p53 staining pattern. Indeed, the MqueTH data were, in part, close to those observed for African Americans, although the Martinican population is highly mixed .