Prevalencia y características de mutaciones somáticas del gen KRAS en pacientes chilenos con cáncer colorrectal / KRAS gene somatic mutations in Chilean patients with colorectal cancer

Background: The molecular testing of KRAS mutation status in metastatic colorectal cancer patients is mandatory to identify patients eligible for anti-epidermal growth factor receptor monoclonal antibody therapy. Aim: To report the frequency of KRAS gene mutations in Chilean patients with colorectal cancer (CRC). Material and Methods: A cohort of 262 Chilean patients with CRC aged 26 to 90 years (53% males), was studied. KRAS mutation status was analyzed by real-time polymerase chain reaction and correlated with clinicopathological data. Results: Ninety-eight patients (37%) were positive for KRAS mutations. G12D was the most common mutation with a frequency of 36.7%, followed by G12V (25.5%), G13D (17.3%), G12A (7.1%), G12C (6.1%), G12S (5.1%) and G12R (2%). The frequency of the mutation in left, right colon and rectal tumors was 37.8, 32.6 and 44.9%, respectively. Among tumors with mutations, 86.7% were well or moderately differentiated tumors and the rest were poorly differentiated. No significant associations between KRAS gene mutations and other clinicopathological features of the tumor were observed. Conclusions: The frequencies of KRAS mutations reported in this study are similar to frequencies reported for European and North-American populations, lower than in a Spanish study and higher than in a Peruvian study.

Cancer screening, reproductive history, socioeconomic status, and anticipated cancer-related behavior among Hmong adults.

In the United States, breast, cervical, colorectal and prostate cancer screening rates are low or non-existent in the Hmong population compared to non-Hispanic Whites. No Hmong adults report ever participating in prostate (male only) and colorectal cancer screening. US-born Hmong women, those living in the US 20 years, and those 39 years old are more likely to be screened for breast and cervical cancer than other women. The Hmong, in general, are a young population (median age = 34 years) with low socioeconomic status. As a function of these characteristics, 52% of Hmong women reported having their first child at 15-19 years old and continued to bear children until 40-54 years old. The combination of young age at first pregnancy and multiparity probably protects Hmong women from breast cancer but elevates cervical cancer risk.

The anatomic distribution of colorectal cancer in a New York City Puerto Rican group

Studies have attempted to define the anatomic distribution of colorectal cancer in some black and white groups of the U.S. However, little, if any research has looked at the regional distribution of colorectal cancer in an American Hispanic, especially Puerto Rican, group. This study attempts to provide some insight into the subsegmental distribution of colorectal cancer in this group of the American population which has a heavy concentration of people in many major U.S. cities. We retrospectively reviewed the charts of Puerto Rican patients who had colorectal adenocarcinoma and were on the files of the tumor registries of two principal teaching hospitals of a New York City medical school from 1976-95, and collected the age and location of the cancers. Patients were self identified as being of Puerto Rican descent. Right colon cancers were from the cecum up to the hepatic flexure, left from the splenic flexure down to the sigmoid colon, rectal which included rectosigmoid, transverse and cancers of unknown locations. The latter were not included in the anatomic analysis since the location was not known. There were eleven of these patients. The anatomic analysis was of 134 patients. There were 67 women, and 78 men with a mean age of 60.3 years, and 63.7 years respectively with an overall mean age of 62.2 years. The anatomic distribution of the cancers were as follows: right colon cancer represented 22.4 or 30/134, transverse lesions equaled 1.5 or 2/134, left cancers were found in 38.0 or 51/134, rectal malignancies equaled 38.0 or 51/134. Previously, it has been shown that the presentation of right sided colorectal cancer in white and black Americans is greater than the 22.4 seen in the Puerto Rican group of this study. However, these previous groups have been found to have 50 of cancers located distal to the splenic flexure, similar to the Puerto Ricans in this study. The average age of Puerto Ricans presenting with colorectal cancer compared to the average age of the general population may be different. Screening techniques for colorectal cancer may be adequate for detecting colorectal cancer in Puerto Ricans, however if they are indeed presenting at a relatively early age, the techniques may need to be applied earlier in comparison to the general American population. Further study is needed to see if the age of presentation is indeed as early as suggested by the present study