KRAS, NRAS, and BRAF Hot-Spot Mutations in Relation to Sidedness of Primary Colorectal Cancer: A Retrospective Cohort Study

Background/Objective: Studies have shown an association between colorectal cancer (CRC) sidedness and gene mutations that may affect CRC clinical behavior. This study examined the association between specific KRAS, NRAS, and BRAF hot-spot mutations and primary CRC sidedness. Methods: We performed a retrospective cohort analysis of 722 patients diagnosed with primary CRC and tested for KRAS, NRAS, and BRAF hot-spot mutations at the University of Texas Medical Branch (UTMB) from January 2016 through July 2023. Multivariable logistic regressions analyses were conducted. Results:KRAS, NRAS, and BRAF hot-spot mutations rates were 37.8%, 4.6%, and 6.1%, respectively. Right-sided primary CRC had the highest prevalence of mutated tumors (64%). KRAS and BRAF hot-spot mutations were significantly different according to tumor sidedness. KRAS p.Gly12Asp, p.Gly12Val, and p.Gly13Asp showed a significantly increased likelihood of right-sided primary CRC compared to KRAS wildtype, 128%, 134%, and 221% higher, respectively. Conversely, KRAS p.Gly12Val and p.Gly13Asp mutations were associated with decreased likelihood of rectal cancer (53% lower) and left-sided tumors (56% lower), respectively. BRAF p.Val600Glu mutation, as opposed to BRAF wildtype, was associated with a 278% higher likelihood of right-sided CRC. No significant associations were observed between NRAS mutations and primary CRC sidedness. Conclusions: In primary CRC, specific mutations in KRAS (p.Gly12Asp, p.Gly12Val, and p.Gly13Asp) and BRAF p.Val600Glu were associated with increased likelihood of right-sided tumors. KRAS p.Gly12Val and p.Gly13Asp mutations were associated with decreased likelihood of rectal cancer and left-sided tumors, respectively. These findings suggest that tumorigenesis and mutational processes differ based on tumor sidedness. Further studies are needed to substantiate these findings.

Incidence of prostate, colorectal and male breast cancers in relation with statins and testosterone replacement therapy: SEER-Medicare 2007-2015

INTRODUCTION

Statins and testosterone replacement therapy (TTh) have been inconsistently associated with a reduced risk of hormone-related cancers (HRCs, prostate [PCa], colorectal [CRC], and male breast cancers [BrCa]). Yet, the joint association of statins and TTh with the incidence of these cancers, and whether these associations vary by race, remains poorly understood. The objective of this retrospective cohort study is to examine the independent and joint effects of pre-diagnostic use of statins and TTh on the risk of HRCs, including PCa, CRC, and male BrCa.

MATERIALS

and Methods: In 105,690 men (≥65 yrs) identified using the SEER-Medicare 2007-2015 data, we identified 82,578 White and 10,256 Black men. Pre-diagnostic prescription of statins and TTh was ascertained for this analysis and categorized into four groups (Neither users, statins alone, TTh alone and Dual users). Multivariable Time-varying Cox proportional hazards and Accelerated Failure Time (AFT) models were performed.

RESULTS

We found inverse joint associations of statins and TTh with incident HRCs before (aHR: 0.39; 95 % CI: 0.35-0.44) and after 3 years of follow-up (aHR: 0.74; 95 % CI: 0.67-0.82). This included a lower risk for advanced stage HRC (only <3 years follow-up). Similar joint associations were identified with incident PCa, aggressive PCa, incident CRC, and its specific right- and left-sided CRC (only <3 years follow-up). In general, the inverse associations persisted among White (mainly <3 years follow-up) and Black men (high-grade HRC and <3 years follow-up). Findings from the AFT analysis were similar.

DISCUSSION

Pre-diagnostic use of statins and TTh were, independently and jointly, associated with reduced risks of HRC and specific cancer sites at three years of follow-up overall, and among White and Black men. Greatest associations of HRCs risk reduction were observed among dual users (statins plus TTh). Further studies are needed to validate these findings, including larger samples of Black men, and male BrCa sites.

Evaluating the impact of pre-diagnostic use of statins and testosterone replacement therapy on mortality outcomes in older men with hormone-related cancers: Surveillance, Epidemiology, and End Results-Medicare 2007-2015

BACKGROUND

The link between the pre-diagnostic use of statins and testosterone replacement therapy and their impact on hormone-related cancers, prostate cancer, colorectal cancer, and male breast cancer survival remains a topic of controversy. Further, there is a knowledge gap concerning the joint effects of statins and testosterone replacement therapy on hormone-related cancer survival outcomes.

OBJECTIVE

To examine the independent and joint effects of pre-diagnostic use of statins and testosterone replacement therapy on the risk of all-cause and cause-specific mortality among older men diagnosed with hormone-related cancers, including prostate cancer, colorectal cancer, and male breast cancer.

METHODS

In 41,707 men (≥65 years) of Surveillance, Epidemiology, and End Results-Medicare 2007-2015, we identified 31,097 prostate cancer, 10,315 colorectal cancer, and 295 male breast cancer cases. Pre-diagnostic prescription of statins and testosterone replacement therapy was ascertained and categorized into four groups (Neither users, statins alone, testosterone replacement therapy alone, and Dual users). Multivariable-adjusted Cox proportional hazards and competing-risks (Fine-Gray subdistribution hazard) models were conducted.

RESULTS

No significant associations were found in Cox-proportional hazard models for hormone-related cancers. However, in the Fine-Gray competing risk models among high-grade hormone-related cancers, statins alone had an 11% reduced risk of hormone-related cancer-specific death (hazard ratio: 0.89; 95% confidence interval: 0.81-0.99; p 0.0451). In the prostate cancer cohort with both statistical models, the use of testosterone replacement therapy alone had a 24% lower risk of all-cause death (hazard ratio: 0.76; 95% confidence interval: 0.59-0.97; p 0.0325) and a 57% lower risk of prostate cancer-specific death (hazard ratio: 0.43; 95% confidence interval: 0.24-0.75; p 0.0029). Similar inverse associations were found among aggressive prostate cancer cases with testosterone replacement therapy alone and statins alone. No significant associations were found in the colorectal cancer and male breast cancer sub-groups.

CONCLUSION

Pre-diagnostic use of statins and testosterone replacement therapy showed a survival benefit with reduced mortality in high-grade hormone-related cancer patients (only statins) and aggressive prostate cancer patients in both statistical models. Findings of testosterone replacement therapy use in aggressive prostate cancer settings could facilitate clinical trials. Further studies with extended follow-up periods are needed to substantiate these findings.

Mortality Outcome Associated with Specific KRAS, NRAS, and BRAF Hot-Spot Mutations in Metastatic Colorectal Cancer Patients: A Retrospective Cohort Study

Background/Objective: The prognostic value of specific hot-spot mutations within KRAS, NRAS, and BRAF genes in metastatic colorectal cancer (mCRC) genes remains debatable. This study explores whether certain KRAS, NRAS, and BRAF mutations are associated with the risk of all-cause mortality in mCRC. Methods: We retrospectively analyzed records of 494 patients with mCRC treated at the University of Texas Medical Branch between January 2016 and July 2023. Data on genetic mutations and clinicopathological features were collected for this analysis. We estimated survival probabilities and conducted multivariable Cox proportional hazards regression to evaluate the impact of specific mutations on all-cause mortality risk. Results:KRAS c.35G>T (p.Gly12Val) and c.34G>T (p.Gly12Cys) mutations were significantly associated with an increased risk of all-cause mortality in the overall mCRC population and the treated mCRC subgroup. KRAS c.38G>A (p.Gly13Asp) was significantly associated with an increased risk of all-cause mortality in the treated mCRC subgroup but BRAF c.1799T>A (p.Val600Glu) was significantly associated with an increased risk of all-cause mortality in the overall mCRC population. No significant association was observed between NRAS mutations and mortality risk in mCRC, possibly due to their lower frequency or different biological effects compared to KRAS and BRAF mutations. Conclusions: These findings suggest that specific KRAS [c.35G>T (p.Gly12Val), c.34G>T (p.Gly12Cys), and c.38G>A (p.Gly13Asp)] and BRAF c.1799T>A (p.Val600Glu) mutations may have prognostic value in mCRC. However, given the single-center study design and lack of direct therapeutic implications, larger multicenter studies are needed to substantiate these results and better define the clinical relevance of these mutations.