Tag Archive for: geneticcounseling

Some driver RET mutations are not observed in Indian cancers

The impact of two driver mutations of RET gene, V804M/L and S891A, on Thyroid cancer was described recently by Pichardo et al in JAMA Otolaryngology, 2023. In a population screening, 75 people were identified to have 2 Pathogenic or Likely Pathogenic (P/LP) germline variants of the RET gene. 20 out of these 75 patients chose to undergo prophylactic thyroidectomy even though they did not have any symptoms of cancer. After surgery, pathological analysis of their tissue detected the growth of medullary or papillary thyroid cancer (PTC) in 12 and 2 patients respectively, i.e., 70% of patients with these 2 mutations had been harboring cancer unknowingly!
We examined the presence of these 2 RET variants in Sapien’s 61 Indian thyroid cancer samples profiled in the OncoMineDx panel by ThermoFisher. P/LP mutations were seen in 4 cases, all below the age of 40. Three cases were PTCs and 1 Follicular, with an overall percentage of 6%. The variants detected were V804M/L (3 cases) and C618Y (1 case, Follicular). No case of S891A mutation was detected.
We also checked for RET mutations in our genetically profiled lung cancers (103 cases) where 28 cases had SNVs with 5 cases of V804M, and 1 case had a fusion. No case of S891A was observed. Similarly, among 449 breast cancers, 280 CRCs, 47 gliomas and few cases each of endometrium, urinary bladder and prostate cancers that have been genetically profiled, many cases of V804M/L and other P/LP RET mutations were observed but none of S891A.

Landscape of Kinase gene fusions in cancers

Tyrosine kinases such as ALK, RET and ROS1 are often activated by translocations or chromosomal rearrangements that result in increased oncogenic activity and are attractive candidates for targeted therapy. In our #biobank, we have identified many patient samples harbouring ALK, RET and ROS1 rearrangements by NGS.

FDA approved drugs such as Crizotinib (Xalkori, #Pfizer), Ceritinib (Zykadia, #Novartis), and Alectinib (Alecensa, #Roche) that target the kinase activity of ALK; Pralsetinib (Gavreto, Roche) targeting RET fusions in NSCLC; Entrectinib (Rozlytrek, Roche) for ROS1+ metastatic NSCLCs, and novel drugs in #clinicaltrials offer promising therapeutic approaches for not just lung but also breast, colorectal and other solid tumours.

ALK targeted therapy for lung cancer: Integration of NGS genome profiling in management of ALK-mutated NSCLCs in India

The NGS genotyping of our NSCLC cases using ThermoFisher’s Oncomine panel identified 8 genetic variants in the ALK gene in 9 cases (16.67%), some of which, such as G1202R and S1206Y surprisingly confer resistance to #Crizotinib treatment, but demonstrate sensitivity to second-generation ALK inhibitors such as #Brigatinib and #Ceritinib, which are currently approved for the treatment of metastatic lung cancers (Sullivan I et al., Ther Adv Med Oncol 2016).

Integration of NGS genetic profiling of tumour samples could play a beneficial role in the management of ALK mutated NSCLCs in India by helping identify the best targeted therapy among Brigatinib, Ceritinib and Crizotinib upfront, based on the mutational profile.