Oncology

Question 1

Cachexia

Answer 1

Pround wt loss
Fat and lean muscle loss
Tumor produces cytokines -> increased BMR

Major causes of cancer death and disability

Question 2

Psammoma bodies

Answer 2

Laminated concentric calcific spherules
Concentric rings of calcium layed down in sheets

“PSaMMoMa”
Papillary thyroid cancer
Serous papillary cystadenocarcinoma of ovary
Malignant Mesothelioma
Meningioma

Question 3

PTHrP secreting tumors

Answer 3

Head and neck squamous cell cancers
Breast cancer
RCC

Question 4

Liver mets

Answer 4

“Cancer Sometimes Penetrates Benign Liver”

Colon
Stomach
Pancreas
Breast
Lung

Elevated LFTs – alkphos
Liver tenderness
Abd pain
Hepatomegaly
Hepatic dysfunction – ascites

Question 5

Brain mets

Answer 5

“Lots of Bad Stuff Kills Glia”

Liver
Breast
Skin – melanoma
Kidney – RCC
GI tract – colon

HA
Focal neurological deficits
Cognitive dysfunction – memory loss, personality changes
Seizures

Question 6

Bone mets

Answer 6

“Permanently Relocated Tumors That Like Bone”

Prostate
Renal cell carcinoma
Testes
Thyroid
Lung
Breast

Question 7

Normal mechanisms to enter S phase of cell cycle

Answer 7

CDK4 activates Cyclin D

• > phosphorylates Rb protein
• > Rb dissociates from E2F
• > progress to S phase

Question 8

Rb mutation

Answer 8

Can’t bind E2F -> rapid G1 -> S

= tumor

Question 9

Four main targets of genetic damage leading to cancer

Answer 9

Proto-oncogenes – uncouple cell from external growth factor signals

Tumor suppressor genes – reg cell cycle – need mutations in both alleles – TWO = TWOmor

Genes that regulate apoptosis -> immortal

DNA repair genes – more susceptible to subsequent damage and mutations

Question 10

Retinoblastoma (Rb)

Answer 10

¼ cases b/l and all b/l are inheritied point mutations
other 2/3 u/l and sporadic

two hits needed

Question 11

P53

Answer 11

Acts through p21 to cause cell cycle arrest

Involved at G1/S and G2/M checkpoints

Binds to damaged dNA -> halt cell cycle -> repair or apoptosis by inducing transcription of BAX or other pro-apoptotic genes

Mutations allow cell to progress through checkpoint despite DNA damage/mutations

Question 12

Oncogenes

Answer 12

ONEcogenes – require ONE mutation -> tumor

Proto-oncogenes: normal cellular genes that regulate cell proliferation and differentiation can become oncogenes

Oncogenes – promote autonomous cell growth in cancer cells by promoting cell growth in absence of normal mitotic signals

Missing regulatory elements = gain of function

Question 13

RAS oncogene

Answer 13

MC
Uncoupled signal from growth factors – always on

K-RAS -> Kolon and panKreatic, and lung
H-RAS -> Hematuria – bladder and kidney tumors
N-RAS -> melanomas, hematologic malignancies, follicular thyroid cancer